/************** ast.js ***************/

"use strict";

function DEFNODE(type, props, methods, base) {
    if (arguments.length < 4) {
        base = AST_Node;//如果最后一个参数没有传，那么默认继承自Node
    }

    if (!props) {
        props = [];
    } else {//拆分Node存在的属性
        props = props.split(/\s+/);
    }
    var self_props = props;

    //复制父类拥有的属性
    if (base && base.PROPS) {
        props = props.concat(base.PROPS);
    }

    //
    var code = "return function AST_" + type + "(props){ if (props) { ";

    for (var i = props.length; --i >= 0;) {
        code += "this." + props[i] + " = props." + props[i] + ";";
    }

    //原型
    var proto = base && new base;

    //如果存在构造函数，则加入构造函数代码
    if (proto && proto.initialize || (methods && methods.initialize)) {
        code += "this.initialize();";
    }

    code += "}}";
    //函数代码拼接完成

    console.log("define node: " + code);

    //将函数文本转化为对象（构造器）
    var ctor = new Function(code)();

    //连接原型链
    if (proto) {
        ctor.prototype = proto;
        ctor.BASE = base;
    }

    //加载子节点类型
    if (base) {
        base.SUBCLASSES.push(ctor);
    }

    ctor.prototype.CTOR = ctor;
    ctor.PROPS = props || null;
    ctor.SELF_PROPS = self_props;
    ctor.SUBCLASSES = [];

    if (type) {
        ctor.prototype.TYPE = ctor.TYPE = type;
    }

    if (methods) {
        for (i in methods) {
            if (HOP(methods, i)) {
                if (/^\$/.test(i)) {//$开头的，认为是文本描述，直接设置到class的属性内部
                    ctor[i.substr(1)] = methods[i];
                } else {
                    ctor.prototype[i] = methods[i];
                }
            }
        }
    }

    //所有node都有定义函数的函数
    ctor.DEFMETHOD = function (name, method) {
        this.prototype[name] = method;
    };

    if (typeof exports !== "undefined") {
        exports["AST_" + type] = ctor;
    }
    return ctor;
}

//token
var AST_Token = DEFNODE("Token"
    , "type value line col pos endline endcol endpos nlb comments_before file raw"
    , {}
    , null);


//所有节点的父类
var AST_Node = DEFNODE("Node", "start end", {
    _clone: function (deep) {
        if (deep) {
            var self = this.clone();
            return self.transform(new TreeTransformer(function (node) {
                if (node !== self) {
                    return node.clone(true);
                }
            }));
        }
        return new this.CTOR(this);
    },
    clone: function (deep) {
        return this._clone(deep);
    },
    $documentation: "Base class of all AST nodes",
    $propdoc: {
        start: "[AST_Token] The first token of this node",
        end: "[AST_Token] The last token of this node"
    },
    _walk: function (visitor) {
        return visitor._visit(this);
    },
    walk: function (visitor) {
        return this._walk(visitor); // not sure the indirection will be any help
    }
}, null);

AST_Node.warn_function = null;

AST_Node.warn = function (txt, props) {
    if (AST_Node.warn_function)
        AST_Node.warn_function(string_template(txt, props));
};

//语句，代表函数执行序列
/* -----[ statements ]----- */

var AST_Statement = DEFNODE("Statement", null, {
    $documentation: "Base class of all statements"
});

var AST_Debugger = DEFNODE("Debugger", null, {
    $documentation: "Represents a debugger statement"
}, AST_Statement);

//指令，特殊的语句，如："use strict" 是ES5支持的一个指令，代表严格模式
var AST_Directive = DEFNODE("Directive", "value scope quote", {
    $documentation: "Represents a directive, like \"use strict\";",
    $propdoc: {
        value: "[string] The value of this directive as a plain string (it's not an AST_String!)",
        scope: "[AST_Scope/S] The scope that this directive affects",
        quote: "[string] the original quote character"
    }
}, AST_Statement);

//简单语句，一般来说是一行
var AST_SimpleStatement = DEFNODE("SimpleStatement", "body", {
    $documentation: "A statement consisting of an expression, i.e. a = 1 + 2",
    $propdoc: {
        body: "[AST_Node] an expression node (should not be instanceof AST_Statement)"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.body._walk(visitor);
        });
    }
}, AST_Statement);

//遍历body的方法
function walk_body(node, visitor) {
    var body = node.body;
    //取出body，如果body是单行 （if，for的语句块，没有花括号的场景 if(a)b;）对单行进行遍历，否则对多行语句的每个语句进行遍历
    if (body instanceof AST_Statement) {
        body._walk(visitor);// _walk是Node具有的一个方法，所以所有的语法节点都将存在这个函数
    }
    else for (var i = 0, len = body.length; i < len; i++) {
        body[i]._walk(visitor);
    }
}

//语句块，代表的是"{}"内部的语句序列，它包含body属性
var AST_Block = DEFNODE("Block", "body", {
    $documentation: "A body of statements (usually bracketed)",
    $propdoc: {
        body: "[AST_Statement*] an array of statements"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            walk_body(this, visitor);
        });
    }
}, AST_Statement);

var AST_BlockStatement = DEFNODE("BlockStatement", null, {
    $documentation: "A block statement"
}, AST_Block);

var AST_EmptyStatement = DEFNODE("EmptyStatement", null, {
    $documentation: "The empty statement (empty block or simply a semicolon)"
}, AST_Statement);

var AST_StatementWithBody = DEFNODE("StatementWithBody", "body", {
    $documentation: "Base class for all statements that contain one nested body: `For`, `ForIn`, `Do`, `While`, `With`",
    $propdoc: {
        body: "[AST_Statement] the body; this should always be present, even if it's an AST_EmptyStatement"
    }
}, AST_Statement);

var AST_LabeledStatement = DEFNODE("LabeledStatement", "label", {
    $documentation: "Statement with a label",
    $propdoc: {
        label: "[AST_Label] a label definition"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.label._walk(visitor);
            this.body._walk(visitor);
        });
    },
    clone: function (deep) {
        var node = this._clone(deep);
        if (deep) {
            var label = node.label;
            var def = this.label;
            node.walk(new TreeWalker(function (node) {
                if (node instanceof AST_LoopControl
                    && node.label && node.label.thedef === def) {
                    node.label.thedef = label;
                    label.references.push(node);
                }
            }));
        }
        return node;
    }
}, AST_StatementWithBody);

var AST_IterationStatement = DEFNODE("IterationStatement", null, {
    $documentation: "Internal class.  All loops inherit from it."
}, AST_StatementWithBody);

var AST_DWLoop = DEFNODE("DWLoop", "condition", {
    $documentation: "Base class for do/while statements",
    $propdoc: {
        condition: "[AST_Node] the loop condition.  Should not be instanceof AST_Statement"
    }
}, AST_IterationStatement);

var AST_Do = DEFNODE("Do", null, {
    $documentation: "A `do` statement",
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.body._walk(visitor);
            this.condition._walk(visitor);
        });
    }
}, AST_DWLoop);

var AST_While = DEFNODE("While", null, {
    $documentation: "A `while` statement",
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.condition._walk(visitor);
            this.body._walk(visitor);
        });
    }
}, AST_DWLoop);

var AST_For = DEFNODE("For", "init condition step", {
    $documentation: "A `for` statement",
    $propdoc: {
        init: "[AST_Node?] the `for` initialization code, or null if empty",
        condition: "[AST_Node?] the `for` termination clause, or null if empty",
        step: "[AST_Node?] the `for` update clause, or null if empty"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            if (this.init) {
                this.init._walk(visitor);
            }
            if (this.condition) {
                this.condition._walk(visitor);
            }
            if (this.step) {
                this.step._walk(visitor);
            }
            this.body._walk(visitor);
        });
    }
}, AST_IterationStatement);

var AST_ForIn = DEFNODE("ForIn", "init name object", {
    $documentation: "A `for ... in` statement",
    $propdoc: {
        init: "[AST_Node] the `for/in` initialization code",
        name: "[AST_SymbolRef?] the loop variable, only if `init` is AST_Var",
        object: "[AST_Node] the object that we're looping through"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.init._walk(visitor);
            this.object._walk(visitor);
            this.body._walk(visitor);
        });
    }
}, AST_IterationStatement);

var AST_With = DEFNODE("With", "expression", {
    $documentation: "A `with` statement",
    $propdoc: {
        expression: "[AST_Node] the `with` expression"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.expression._walk(visitor);
            this.body._walk(visitor);
        });
    }
}, AST_StatementWithBody);

//作用域相关
/* -----[ scope and functions ]----- */

var AST_Scope = DEFNODE("Scope", "directives variables functions uses_with uses_eval parent_scope enclosed cname", {
    $documentation: "Base class for all statements introducing a lexical scope",
    $propdoc: {
        directives: "[string*/S] an array of directives declared in this scope",
        variables: "[Object/S] a map of name -> SymbolDef for all variables/functions defined in this scope",
        functions: "[Object/S] like `variables`, but only lists function declarations",
        uses_with: "[boolean/S] tells whether this scope uses the `with` statement",
        uses_eval: "[boolean/S] tells whether this scope contains a direct call to the global `eval`",
        parent_scope: "[AST_Scope?/S] link to the parent scope",
        enclosed: "[SymbolDef*/S] a list of all symbol definitions that are accessed from this scope or any subscopes",
        cname: "[integer/S] current index for mangling variables (used internally by the mangler)"
    }
}, AST_Block);

var AST_Toplevel = DEFNODE("Toplevel", "globals", {
    $documentation: "The toplevel scope",
    $propdoc: {
        globals: "[Object/S] a map of name -> SymbolDef for all undeclared names"
    },
    wrap_commonjs: function (name) {
        var body = this.body;
        var wrapped_tl = "(function(exports){'$ORIG';})(typeof " + name + "=='undefined'?(" + name + "={}):" + name + ");";
        wrapped_tl = parse(wrapped_tl);
        wrapped_tl = wrapped_tl.transform(new TreeTransformer(function before(node) {
            if (node instanceof AST_Directive && node.value == "$ORIG") {
                return MAP.splice(body);
            }
        }));
        return wrapped_tl;
    }
}, AST_Scope);

//匿名函数的基类，其实是所有函数的基类。在模型层面，普通函数相对于匿名函数只是会多一些属性
var AST_Lambda = DEFNODE("Lambda", "name argnames uses_arguments", {
    $documentation: "Base class for functions",
    $propdoc: {
        name: "[AST_SymbolDeclaration?] the name of this function",
        argnames: "[AST_SymbolFunarg*] array of function arguments",
        uses_arguments: "[boolean/S] tells whether this function accesses the arguments array"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            if (this.name) this.name._walk(visitor);
            var argnames = this.argnames;
            for (var i = 0, len = argnames.length; i < len; i++) {
                argnames[i]._walk(visitor);
            }
            walk_body(this, visitor);
        });
    }
}, AST_Scope);

//getter 和setter
var AST_Accessor = DEFNODE("Accessor", null, {
    $documentation: "A setter/getter function.  The `name` property is always null."
}, AST_Lambda);

//函数表达式 var a = function(){}
var AST_Function = DEFNODE("Function", null, {
    $documentation: "A function expression"
}, AST_Lambda);

//函数声明 function a(){}
var AST_Defun = DEFNODE("Defun", null, {
    $documentation: "A function definition"
}, AST_Lambda);

/* -----[ JUMPS ]----- */

var AST_Jump = DEFNODE("Jump", null, {
    $documentation: "Base class for “jumps” (for now that's `return`, `throw`, `break` and `continue`)"
}, AST_Statement);

var AST_Exit = DEFNODE("Exit", "value", {
    $documentation: "Base class for “exits” (`return` and `throw`)",
    $propdoc: {
        value: "[AST_Node?] the value returned or thrown by this statement; could be null for AST_Return"
    },
    _walk: function (visitor) {
        return visitor._visit(this, this.value && function () {
                this.value._walk(visitor);
            });
    }
}, AST_Jump);

var AST_Return = DEFNODE("Return", null, {
    $documentation: "A `return` statement"
}, AST_Exit);

var AST_Throw = DEFNODE("Throw", null, {
    $documentation: "A `throw` statement"
}, AST_Exit);

var AST_LoopControl = DEFNODE("LoopControl", "label", {
    $documentation: "Base class for loop control statements (`break` and `continue`)",
    $propdoc: {
        label: "[AST_LabelRef?] the label, or null if none"
    },
    _walk: function (visitor) {
        return visitor._visit(this, this.label && function () {
                this.label._walk(visitor);
            });
    }
}, AST_Jump);

var AST_Break = DEFNODE("Break", null, {
    $documentation: "A `break` statement"
}, AST_LoopControl);

var AST_Continue = DEFNODE("Continue", null, {
    $documentation: "A `continue` statement"
}, AST_LoopControl);

/* -----[ IF ]----- */

var AST_If = DEFNODE("If", "condition alternative", {
    $documentation: "A `if` statement",
    $propdoc: {
        condition: "[AST_Node] the `if` condition",
        alternative: "[AST_Statement?] the `else` part, or null if not present"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.condition._walk(visitor);
            this.body._walk(visitor);
            if (this.alternative) this.alternative._walk(visitor);
        });
    }
}, AST_StatementWithBody);

/* -----[ SWITCH ]----- */

var AST_Switch = DEFNODE("Switch", "expression", {
    $documentation: "A `switch` statement",
    $propdoc: {
        expression: "[AST_Node] the `switch` “discriminant”"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.expression._walk(visitor);
            walk_body(this, visitor);
        });
    }
}, AST_Block);

var AST_SwitchBranch = DEFNODE("SwitchBranch", null, {
    $documentation: "Base class for `switch` branches",
}, AST_Block);

var AST_Default = DEFNODE("Default", null, {
    $documentation: "A `default` switch branch",
}, AST_SwitchBranch);

var AST_Case = DEFNODE("Case", "expression", {
    $documentation: "A `case` switch branch",
    $propdoc: {
        expression: "[AST_Node] the `case` expression"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.expression._walk(visitor);
            walk_body(this, visitor);
        });
    }
}, AST_SwitchBranch);

/* -----[ EXCEPTIONS ]----- */

var AST_Try = DEFNODE("Try", "bcatch bfinally", {
    $documentation: "A `try` statement",
    $propdoc: {
        bcatch: "[AST_Catch?] the catch block, or null if not present",
        bfinally: "[AST_Finally?] the finally block, or null if not present"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            walk_body(this, visitor);
            if (this.bcatch) this.bcatch._walk(visitor);
            if (this.bfinally) this.bfinally._walk(visitor);
        });
    }
}, AST_Block);

var AST_Catch = DEFNODE("Catch", "argname", {
    $documentation: "A `catch` node; only makes sense as part of a `try` statement",
    $propdoc: {
        argname: "[AST_SymbolCatch] symbol for the exception"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.argname._walk(visitor);
            walk_body(this, visitor);
        });
    }
}, AST_Block);

var AST_Finally = DEFNODE("Finally", null, {
    $documentation: "A `finally` node; only makes sense as part of a `try` statement"
}, AST_Block);

/* -----[ VAR ]----- */

var AST_Definitions = DEFNODE("Definitions", "definitions", {
    $documentation: "Base class for `var` nodes (variable declarations/initializations)",
    $propdoc: {
        definitions: "[AST_VarDef*] array of variable definitions"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            var definitions = this.definitions;
            for (var i = 0, len = definitions.length; i < len; i++) {
                definitions[i]._walk(visitor);
            }
        });
    }
}, AST_Statement);

var AST_Var = DEFNODE("Var", null, {
    $documentation: "A `var` statement"
}, AST_Definitions);

var AST_VarDef = DEFNODE("VarDef", "name value", {
    $documentation: "A variable declaration; only appears in a AST_Definitions node",
    $propdoc: {
        name: "[AST_SymbolVar] name of the variable",
        value: "[AST_Node?] initializer, or null of there's no initializer"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.name._walk(visitor);
            if (this.value) this.value._walk(visitor);
        });
    }
});

/* -----[ OTHER ]----- */

var AST_Call = DEFNODE("Call", "expression args", {
    $documentation: "A function call expression",
    $propdoc: {
        expression: "[AST_Node] expression to invoke as function",
        args: "[AST_Node*] array of arguments"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            var args = this.args;
            for (var i = 0, len = args.length; i < len; i++) {
                args[i]._walk(visitor);
            }
            this.expression._walk(visitor);
        });
    }
});

var AST_New = DEFNODE("New", null, {
    $documentation: "An object instantiation.  Derives from a function call since it has exactly the same properties"
}, AST_Call);

var AST_Sequence = DEFNODE("Sequence", "expressions", {
    $documentation: "A sequence expression (comma-separated expressions)",
    $propdoc: {
        expressions: "[AST_Node*] array of expressions (at least two)"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.expressions.forEach(function (node) {
                node._walk(visitor);
            });
        });
    }
});

var AST_PropAccess = DEFNODE("PropAccess", "expression property", {
    $documentation: "Base class for property access expressions, i.e. `a.foo` or `a[\"foo\"]`",
    $propdoc: {
        expression: "[AST_Node] the “container” expression",
        property: "[AST_Node|string] the property to access.  For AST_Dot this is always a plain string, while for AST_Sub it's an arbitrary AST_Node"
    }
});

var AST_Dot = DEFNODE("Dot", null, {
    $documentation: "A dotted property access expression",
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.expression._walk(visitor);
        });
    }
}, AST_PropAccess);

var AST_Sub = DEFNODE("Sub", null, {
    $documentation: "Index-style property access, i.e. `a[\"foo\"]`",
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.expression._walk(visitor);
            this.property._walk(visitor);
        });
    }
}, AST_PropAccess);

var AST_Unary = DEFNODE("Unary", "operator expression", {
    $documentation: "Base class for unary expressions",
    $propdoc: {
        operator: "[string] the operator",
        expression: "[AST_Node] expression that this unary operator applies to"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.expression._walk(visitor);
        });
    }
});

var AST_UnaryPrefix = DEFNODE("UnaryPrefix", null, {
    $documentation: "Unary prefix expression, i.e. `typeof i` or `++i`"
}, AST_Unary);

var AST_UnaryPostfix = DEFNODE("UnaryPostfix", null, {
    $documentation: "Unary postfix expression, i.e. `i++`"
}, AST_Unary);

var AST_Binary = DEFNODE("Binary", "operator left right", {
    $documentation: "Binary expression, i.e. `a + b`",
    $propdoc: {
        left: "[AST_Node] left-hand side expression",
        operator: "[string] the operator",
        right: "[AST_Node] right-hand side expression"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.left._walk(visitor);
            this.right._walk(visitor);
        });
    }
});

var AST_Conditional = DEFNODE("Conditional", "condition consequent alternative", {
    $documentation: "Conditional expression using the ternary operator, i.e. `a ? b : c`",
    $propdoc: {
        condition: "[AST_Node]",
        consequent: "[AST_Node]",
        alternative: "[AST_Node]"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.condition._walk(visitor);
            this.consequent._walk(visitor);
            this.alternative._walk(visitor);
        });
    }
});

var AST_Assign = DEFNODE("Assign", null, {
    $documentation: "An assignment expression — `a = b + 5`",
}, AST_Binary);

/* -----[ LITERALS ]----- */

var AST_Array = DEFNODE("Array", "elements", {
    $documentation: "An array literal",
    $propdoc: {
        elements: "[AST_Node*] array of elements"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            var elements = this.elements;
            for (var i = 0, len = elements.length; i < len; i++) {
                elements[i]._walk(visitor);
            }
        });
    }
});

var AST_Object = DEFNODE("Object", "properties", {
    $documentation: "An object literal",
    $propdoc: {
        properties: "[AST_ObjectProperty*] array of properties"
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            var properties = this.properties;
            for (var i = 0, len = properties.length; i < len; i++) {
                properties[i]._walk(visitor);
            }
        });
    }
});

var AST_ObjectProperty = DEFNODE("ObjectProperty", "key value", {
    $documentation: "Base class for literal object properties",
    $propdoc: {
        key: "[string] the property name converted to a string for ObjectKeyVal.  For setters and getters this is an AST_SymbolAccessor.",
        value: "[AST_Node] property value.  For setters and getters this is an AST_Accessor."
    },
    _walk: function (visitor) {
        return visitor._visit(this, function () {
            this.value._walk(visitor);
        });
    }
});

var AST_ObjectKeyVal = DEFNODE("ObjectKeyVal", "quote", {
    $documentation: "A key: value object property",
    $propdoc: {
        quote: "[string] the original quote character"
    }
}, AST_ObjectProperty);

var AST_ObjectSetter = DEFNODE("ObjectSetter", null, {
    $documentation: "An object setter property",
}, AST_ObjectProperty);

var AST_ObjectGetter = DEFNODE("ObjectGetter", null, {
    $documentation: "An object getter property",
}, AST_ObjectProperty);

var AST_Symbol = DEFNODE("Symbol", "scope name thedef", {
    $propdoc: {
        name: "[string] name of this symbol",
        scope: "[AST_Scope/S] the current scope (not necessarily the definition scope)",
        thedef: "[SymbolDef/S] the definition of this symbol"
    },
    $documentation: "Base class for all symbols",
});

var AST_SymbolAccessor = DEFNODE("SymbolAccessor", null, {
    $documentation: "The name of a property accessor (setter/getter function)"
}, AST_Symbol);

var AST_SymbolDeclaration = DEFNODE("SymbolDeclaration", "init", {
    $documentation: "A declaration symbol (symbol in var, function name or argument, symbol in catch)",
}, AST_Symbol);

var AST_SymbolVar = DEFNODE("SymbolVar", null, {
    $documentation: "Symbol defining a variable",
}, AST_SymbolDeclaration);

var AST_SymbolFunarg = DEFNODE("SymbolFunarg", null, {
    $documentation: "Symbol naming a function argument",
}, AST_SymbolVar);

var AST_SymbolDefun = DEFNODE("SymbolDefun", null, {
    $documentation: "Symbol defining a function",
}, AST_SymbolDeclaration);

var AST_SymbolLambda = DEFNODE("SymbolLambda", null, {
    $documentation: "Symbol naming a function expression",
}, AST_SymbolDeclaration);

var AST_SymbolCatch = DEFNODE("SymbolCatch", null, {
    $documentation: "Symbol naming the exception in catch",
}, AST_SymbolDeclaration);

var AST_Label = DEFNODE("Label", "references", {
    $documentation: "Symbol naming a label (declaration)",
    $propdoc: {
        references: "[AST_LoopControl*] a list of nodes referring to this label"
    },
    initialize: function () {
        this.references = [];
        this.thedef = this;
    }
}, AST_Symbol);

var AST_SymbolRef = DEFNODE("SymbolRef", null, {
    $documentation: "Reference to some symbol (not definition/declaration)",
}, AST_Symbol);

var AST_LabelRef = DEFNODE("LabelRef", null, {
    $documentation: "Reference to a label symbol",
}, AST_Symbol);

var AST_This = DEFNODE("This", null, {
    $documentation: "The `this` symbol",
}, AST_Symbol);

var AST_Constant = DEFNODE("Constant", null, {
    $documentation: "Base class for all constants",
    getValue: function () {
        return this.value;
    }
});

var AST_String = DEFNODE("String", "value quote", {
    $documentation: "A string literal",
    $propdoc: {
        value: "[string] the contents of this string",
        quote: "[string] the original quote character"
    }
}, AST_Constant);

var AST_Number = DEFNODE("Number", "value literal", {
    $documentation: "A number literal",
    $propdoc: {
        value: "[number] the numeric value",
        literal: "[string] numeric value as string (optional)"
    }
}, AST_Constant);

var AST_RegExp = DEFNODE("RegExp", "value", {
    $documentation: "A regexp literal",
    $propdoc: {
        value: "[RegExp] the actual regexp"
    }
}, AST_Constant);

var AST_Atom = DEFNODE("Atom", null, {
    $documentation: "Base class for atoms",
}, AST_Constant);

var AST_Null = DEFNODE("Null", null, {
    $documentation: "The `null` atom",
    value: null
}, AST_Atom);

var AST_NaN = DEFNODE("NaN", null, {
    $documentation: "The impossible value",
    value: 0 / 0
}, AST_Atom);

var AST_Undefined = DEFNODE("Undefined", null, {
    $documentation: "The `undefined` value",
    value: (function () {
    }())
}, AST_Atom);

var AST_Hole = DEFNODE("Hole", null, {
    $documentation: "A hole in an array",
    value: (function () {
    }())
}, AST_Atom);

var AST_Infinity = DEFNODE("Infinity", null, {
    $documentation: "The `Infinity` value",
    value: 1 / 0
}, AST_Atom);

var AST_Boolean = DEFNODE("Boolean", null, {
    $documentation: "Base class for booleans",
}, AST_Atom);

var AST_False = DEFNODE("False", null, {
    $documentation: "The `false` atom",
    value: false
}, AST_Boolean);

var AST_True = DEFNODE("True", null, {
    $documentation: "The `true` atom",
    value: true
}, AST_Boolean);

/* -----[ TreeWalker ]----- */

function TreeWalker(callback) {
    this.visit = callback;
    this.stack = [];
    this.directives = Object.create(null);
}


TreeWalker.prototype = {
    _visit: function (node, descend) {
        this.push(node);
        //遍历规则，尝试用外部传递的遍历规则( visit 函数)遍历，如果外部遍历函数返回值为false，
        // 则证明外部遍历器没有定义子树递归规则。使用节点默认递归规则
        var ret = this.visit(node, descend ? function () {
            descend.call(node);
        } : noop);
        if (!ret && descend) {
            descend.call(node);
        }
        this.pop();
        return ret;
    },
    parent: function (n) {//当前节点的上n个节点
        return this.stack[this.stack.length - 2 - (n || 0)];
    },
    push: function (node) {
        if (node instanceof AST_Lambda) {
            this.directives = Object.create(this.directives);
        } else if (node instanceof AST_Directive && !this.directives[node.value]) {
            this.directives[node.value] = node;
        }
        this.stack.push(node);
    },
    pop: function () {
        if (this.stack.pop() instanceof AST_Lambda) {
            this.directives = Object.getPrototypeOf(this.directives);
        }
    },
    self: function () {
        return this.stack[this.stack.length - 1];
    },
    find_parent: function (type) {
        var stack = this.stack;
        for (var i = stack.length; --i >= 0;) {
            var x = stack[i];
            if (x instanceof type) {
                return x;
            }
        }
    },
    has_directive: function (type) {
        var dir = this.directives[type];
        if (dir) {
            return dir;
        }
        var node = this.stack[this.stack.length - 1];
        if (node instanceof AST_Scope) {
            for (var i = 0; i < node.body.length; ++i) {
                var st = node.body[i];

                if (!(st instanceof AST_Directive)) {
                    break;
                }

                if (st.value == type) {
                    return st;
                }
            }
        }
    },
    in_boolean_context: function () {
        var stack = this.stack;
        var i = stack.length, self = stack[--i];
        while (i > 0) {
            var p = stack[--i];
            if ((p instanceof AST_If && p.condition === self) ||
                (p instanceof AST_Conditional && p.condition === self) ||
                (p instanceof AST_DWLoop && p.condition === self) ||
                (p instanceof AST_For && p.condition === self) ||
                (p instanceof AST_UnaryPrefix && p.operator == "!" && p.expression === self)) {
                return true;
            }

            if (!(p instanceof AST_Binary && (p.operator == "&&" || p.operator == "||"))) {
                return false;
            }

            self = p;
        }
    },
    loopcontrol_target: function (node) {
        var stack = this.stack;
        if (node.label) {
            for (var i = stack.length; --i >= 0;) {
                var x = stack[i];

                if (x instanceof AST_LabeledStatement && x.label.name == node.label.name) {
                    return x.body;
                }
            }
        } else {
            for (var i = stack.length; --i >= 0;) {
                var x = stack[i];
                if (x instanceof AST_IterationStatement
                    || node instanceof AST_Break && x instanceof AST_Switch) {
                    return x;
                }
            }
        }
    }
};



/****************** transform.js *********************/
// Tree transformer helpers.

function TreeTransformer(before, after) {
    TreeWalker.call(this);
    this.before = before;
    this.after = after;
}
TreeTransformer.prototype = new TreeWalker;

(function (undefined) {

    function _(node, descend) {
        node.DEFMETHOD("transform", function (tw, in_list) {
            var x, y;
            tw.push(this);
            if (tw.before) x = tw.before(this, descend, in_list);
            if (x === undefined) {
                if (!tw.after) {
                    x = this;
                    descend(x, tw);
                } else {
                    tw.stack[tw.stack.length - 1] = x = this;
                    descend(x, tw);
                    y = tw.after(x, in_list);
                    if (y !== undefined) x = y;
                }
            }
            tw.pop();
            return x;
        });
    };

    function do_list(list, tw) {
        return MAP(list, function (node) {
            return node.transform(tw, true);
        });
    };

    _(AST_Node, noop);

    _(AST_LabeledStatement, function (self, tw) {
        self.label = self.label.transform(tw);
        self.body = self.body.transform(tw);
    });

    _(AST_SimpleStatement, function (self, tw) {
        self.body = self.body.transform(tw);
    });

    _(AST_Block, function (self, tw) {
        self.body = do_list(self.body, tw);
    });

    _(AST_DWLoop, function (self, tw) {
        self.condition = self.condition.transform(tw);
        self.body = self.body.transform(tw);
    });

    _(AST_For, function (self, tw) {
        if (self.init) self.init = self.init.transform(tw);
        if (self.condition) self.condition = self.condition.transform(tw);
        if (self.step) self.step = self.step.transform(tw);
        self.body = self.body.transform(tw);
    });

    _(AST_ForIn, function (self, tw) {
        self.init = self.init.transform(tw);
        self.object = self.object.transform(tw);
        self.body = self.body.transform(tw);
    });

    _(AST_With, function (self, tw) {
        self.expression = self.expression.transform(tw);
        self.body = self.body.transform(tw);
    });

    _(AST_Exit, function (self, tw) {
        if (self.value) self.value = self.value.transform(tw);
    });

    _(AST_LoopControl, function (self, tw) {
        if (self.label) self.label = self.label.transform(tw);
    });

    _(AST_If, function (self, tw) {
        self.condition = self.condition.transform(tw);
        self.body = self.body.transform(tw);
        if (self.alternative) self.alternative = self.alternative.transform(tw);
    });

    _(AST_Switch, function (self, tw) {
        self.expression = self.expression.transform(tw);
        self.body = do_list(self.body, tw);
    });

    _(AST_Case, function (self, tw) {
        self.expression = self.expression.transform(tw);
        self.body = do_list(self.body, tw);
    });

    _(AST_Try, function (self, tw) {
        self.body = do_list(self.body, tw);
        if (self.bcatch) self.bcatch = self.bcatch.transform(tw);
        if (self.bfinally) self.bfinally = self.bfinally.transform(tw);
    });

    _(AST_Catch, function (self, tw) {
        self.argname = self.argname.transform(tw);
        self.body = do_list(self.body, tw);
    });

    _(AST_Definitions, function (self, tw) {
        self.definitions = do_list(self.definitions, tw);
    });

    _(AST_VarDef, function (self, tw) {
        self.name = self.name.transform(tw);
        if (self.value) self.value = self.value.transform(tw);
    });

    _(AST_Lambda, function (self, tw) {
        if (self.name) self.name = self.name.transform(tw);
        self.argnames = do_list(self.argnames, tw);
        self.body = do_list(self.body, tw);
    });

    _(AST_Call, function (self, tw) {
        self.expression = self.expression.transform(tw);
        self.args = do_list(self.args, tw);
    });

    _(AST_Sequence, function (self, tw) {
        self.expressions = do_list(self.expressions, tw);
    });

    _(AST_Dot, function (self, tw) {
        self.expression = self.expression.transform(tw);
    });

    _(AST_Sub, function (self, tw) {
        self.expression = self.expression.transform(tw);
        self.property = self.property.transform(tw);
    });

    _(AST_Unary, function (self, tw) {
        self.expression = self.expression.transform(tw);
    });

    _(AST_Binary, function (self, tw) {
        self.left = self.left.transform(tw);
        self.right = self.right.transform(tw);
    });

    _(AST_Conditional, function (self, tw) {
        self.condition = self.condition.transform(tw);
        self.consequent = self.consequent.transform(tw);
        self.alternative = self.alternative.transform(tw);
    });

    _(AST_Array, function (self, tw) {
        self.elements = do_list(self.elements, tw);
    });

    _(AST_Object, function (self, tw) {
        self.properties = do_list(self.properties, tw);
    });

    _(AST_ObjectProperty, function (self, tw) {
        self.value = self.value.transform(tw);
    });

})();

/***************** utils.js ********************/

function slice(a, start) {
    return Array.prototype.slice.call(a, start || 0);
};

function characters(str) {
    return str.split("");
};

function member(name, array) {
    return array.indexOf(name) >= 0;
};

function find_if(func, array) {
    for (var i = 0, n = array.length; i < n; ++i) {
        if (func(array[i]))
            return array[i];
    }
};

function repeat_string(str, i) {
    if (i <= 0) return "";
    if (i == 1) return str;
    var d = repeat_string(str, i >> 1);
    d += d;
    if (i & 1) d += str;
    return d;
};

function configure_error_stack(fn) {
    Object.defineProperty(fn.prototype, "stack", {
        get: function () {
            var err = new Error(this.message);
            err.name = this.name;
            try {
                throw err;
            } catch (e) {
                return e.stack;
            }
        }
    });
}

function DefaultsError(msg, defs) {
    this.message = msg;
    this.defs = defs;
};
DefaultsError.prototype = Object.create(Error.prototype);
DefaultsError.prototype.constructor = DefaultsError;
DefaultsError.prototype.name = "DefaultsError";
configure_error_stack(DefaultsError);

DefaultsError.croak = function (msg, defs) {
    throw new DefaultsError(msg, defs);
};

function defaults(args, defs, croak) {
    if (args === true) {
        args = {};
    }
    var ret = args || {};

    if (croak) {
        for (var i in ret) {
            if (HOP(ret, i) && !HOP(defs, i)) {
                DefaultsError.croak("`" + i + "` is not a supported option", defs);
            }
        }
    }

    for (var i in defs) {
        if (HOP(defs, i)) {
            ret[i] = (args && HOP(args, i)) ? args[i] : defs[i];
        }
    }
    return ret;
};

function merge(obj, ext) {
    var count = 0;
    for (var i in ext) {

        if (HOP(ext, i)) {
            obj[i] = ext[i];
            count++;
        }
    }
    return count;
};

function noop() {
}
function return_false() {
    return false;
}
function return_true() {
    return true;
}
function return_this() {
    return this;
}
function return_null() {
    return null;
}

var MAP = (function () {
    function MAP(a, f, backwards) {
        var ret = [], top = [], i;

        function doit() {
            var val = f(a[i], i);
            var is_last = val instanceof Last;
            if (is_last) val = val.v;
            if (val instanceof AtTop) {
                val = val.v;
                if (val instanceof Splice) {
                    top.push.apply(top, backwards ? val.v.slice().reverse() : val.v);
                } else {
                    top.push(val);
                }
            }
            else if (val !== skip) {
                if (val instanceof Splice) {
                    ret.push.apply(ret, backwards ? val.v.slice().reverse() : val.v);
                } else {
                    ret.push(val);
                }
            }
            return is_last;
        };
        if (a instanceof Array) {
            if (backwards) {
                for (i = a.length; --i >= 0;) if (doit()) break;
                ret.reverse();
                top.reverse();
            } else {
                for (i = 0; i < a.length; ++i) if (doit()) break;
            }
        }
        else {
            for (i in a) if (HOP(a, i)) if (doit()) break;
        }
        return top.concat(ret);
    };
    MAP.at_top = function (val) {
        return new AtTop(val)
    };
    MAP.splice = function (val) {
        return new Splice(val)
    };
    MAP.last = function (val) {
        return new Last(val)
    };
    var skip = MAP.skip = {};

    function AtTop(val) {
        this.v = val
    };
    function Splice(val) {
        this.v = val
    };
    function Last(val) {
        this.v = val
    };
    return MAP;
})();

function push_uniq(array, el) {
    if (array.indexOf(el) < 0)
        array.push(el);
};

function string_template(text, props) {
    return text.replace(/\{(.+?)\}/g, function (str, p) {
        return props && props[p];
    });
};

function remove(array, el) {
    for (var i = array.length; --i >= 0;) {
        if (array[i] === el) array.splice(i, 1);
    }
};

function mergeSort(array, cmp) {
    if (array.length < 2) return array.slice();
    function merge(a, b) {
        var r = [], ai = 0, bi = 0, i = 0;
        while (ai < a.length && bi < b.length) {
            cmp(a[ai], b[bi]) <= 0
                ? r[i++] = a[ai++]
                : r[i++] = b[bi++];
        }
        if (ai < a.length) r.push.apply(r, a.slice(ai));
        if (bi < b.length) r.push.apply(r, b.slice(bi));
        return r;
    };
    function _ms(a) {
        if (a.length <= 1)
            return a;
        var m = Math.floor(a.length / 2), left = a.slice(0, m), right = a.slice(m);
        left = _ms(left);
        right = _ms(right);
        return merge(left, right);
    };
    return _ms(array);
};

function set_difference(a, b) {
    return a.filter(function (el) {
        return b.indexOf(el) < 0;
    });
};

function set_intersection(a, b) {
    return a.filter(function (el) {
        return b.indexOf(el) >= 0;
    });
};

// this function is taken from Acorn [1], written by Marijn Haverbeke
// [1] https://github.com/marijnh/acorn
function makePredicate(words) {
    if (!(words instanceof Array)) words = words.split(" ");
    var f = "", cats = [];
    out: for (var i = 0; i < words.length; ++i) {
        for (var j = 0; j < cats.length; ++j)
            if (cats[j][0].length == words[i].length) {
                cats[j].push(words[i]);
                continue out;
            }
        cats.push([words[i]]);
    }
    function quote(word) {
        return JSON.stringify(word).replace(/[\u2028\u2029]/g, function (s) {
            switch (s) {
                case "\u2028":
                    return "\\u2028";
                case "\u2029":
                    return "\\u2029";
            }
            return s;
        });
    }

    function compareTo(arr) {
        if (arr.length == 1) return f += "return str === " + quote(arr[0]) + ";";
        f += "switch(str){";
        for (var i = 0; i < arr.length; ++i) f += "case " + quote(arr[i]) + ":";
        f += "return true}return false;";
    }

    // When there are more than three length categories, an outer
    // switch first dispatches on the lengths, to save on comparisons.
    if (cats.length > 3) {
        cats.sort(function (a, b) {
            return b.length - a.length;
        });
        f += "switch(str.length){";
        for (var i = 0; i < cats.length; ++i) {
            var cat = cats[i];
            f += "case " + cat[0].length + ":";
            compareTo(cat);
        }
        f += "}";
        // Otherwise, simply generate a flat `switch` statement.
    } else {
        compareTo(words);
    }
    return new Function("str", f);
};

function all(array, predicate) {
    for (var i = array.length; --i >= 0;)
        if (!predicate(array[i]))
            return false;
    return true;
};

function Dictionary() {
    this._values = Object.create(null);
    this._size = 0;
};
Dictionary.prototype = {
    set: function (key, val) {
        if (!this.has(key)) ++this._size;
        this._values["$" + key] = val;
        return this;
    },
    add: function (key, val) {
        if (this.has(key)) {
            this.get(key).push(val);
        } else {
            this.set(key, [val]);
        }
        return this;
    },
    get: function (key) {
        return this._values["$" + key]
    },
    del: function (key) {
        if (this.has(key)) {
            --this._size;
            delete this._values["$" + key];
        }
        return this;
    },
    has: function (key) {
        return ("$" + key) in this._values
    },
    each: function (f) {
        for (var i in this._values)
            f(this._values[i], i.substr(1));
    },
    size: function () {
        return this._size;
    },
    map: function (f) {
        var ret = [];
        for (var i in this._values)
            ret.push(f(this._values[i], i.substr(1)));
        return ret;
    },
    toObject: function () {
        return this._values
    }
};
Dictionary.fromObject = function (obj) {
    var dict = new Dictionary();
    dict._size = merge(dict._values, obj);
    return dict;
};


function HOP(obj, prop) {
    return Object.prototype.hasOwnProperty.call(obj, prop);
}

// return true if the node at the top of the stack (that means the
// innermost node in the current output) is lexically the first in
// a statement.
function first_in_statement(stack) {
    var node = stack.parent(-1);
    for (var i = 0, p; p = stack.parent(i); i++) {
        if (p instanceof AST_Statement && p.body === node)
            return true;
        if ((p instanceof AST_Sequence && p.expressions[0] === node) ||
            (p instanceof AST_Call && p.expression === node && !(p instanceof AST_New) ) ||
            (p instanceof AST_Dot && p.expression === node ) ||
            (p instanceof AST_Sub && p.expression === node ) ||
            (p instanceof AST_Conditional && p.condition === node  ) ||
            (p instanceof AST_Binary && p.left === node       ) ||
            (p instanceof AST_UnaryPostfix && p.expression === node )) {
            node = p;
        } else {
            return false;
        }
    }
}


/*********** compress.js ************/

function Compressor(options, false_by_default) {
    if (!(this instanceof Compressor)) {
        return new Compressor(options, false_by_default);
    }

    TreeTransformer.call(this, this.before, this.after);

    this.options = defaults(options, {
        booleans: !false_by_default,//优化boolean选项，连续的boolean叠加会被简化
        cascade: !false_by_default,//弱弱地优化一下连续声明, 将 x, x 转成 x，x = something(), x 转成 x = something()
        collapse_vars: !false_by_default,//当 var 和 const 单独使用时尽量合并
        comparisons: !false_by_default,//把结果必然的运算优化成二元运算，例如!(a <= b) → a > b (只有设置了 unsafe_comps时才生效)；尽量转成否运算。例如 a = !b && !c && !d && !e → a=!(b||c||d||e)
        conditionals: !false_by_default,//优化if等判断以及条件选择
        dead_code: !false_by_default,
        drop_console: false,
        drop_debugger: !false_by_default,
        evaluate: !false_by_default,
        expression: false,
        global_defs: {},
        hoist_funs: !false_by_default,
        hoist_vars: false,
        ie8: false,
        if_return: !false_by_default,
        inline: !false_by_default,
        join_vars: !false_by_default,
        keep_fargs: true,
        keep_fnames: false,
        keep_infinity: false,
        loops: !false_by_default,
        negate_iife: !false_by_default,
        passes: 1,
        properties: !false_by_default,
        pure_getters: !false_by_default && "strict",
        pure_funcs: null,
        reduce_vars: !false_by_default,
        sequences: !false_by_default,
        side_effects: !false_by_default,
        switches: !false_by_default,
        top_retain: null,
        toplevel: !!(options && options["top_retain"]),
        typeofs: !false_by_default,
        unsafe: false,
        unsafe_comps: false,
        unsafe_Func: false,
        unsafe_math: false,
        unsafe_proto: false,
        unsafe_regexp: false,
        unused: !false_by_default,
        warnings: false
    }, true);

    // console.log( JSON.stringify(this.options));
    var global_defs = this.options["global_defs"];

    if (typeof global_defs == "object") {
        for (var key in global_defs) {
            if (/^@/.test(key) && HOP(global_defs, key)) {
                global_defs[key.slice(1)] = parse(global_defs[key], {
                    expression: true
                });
            }
        }
    }

    var pure_funcs = this.options["pure_funcs"];
    if (typeof pure_funcs == "function") {
        this.pure_funcs = pure_funcs;
    } else {
        this.pure_funcs = pure_funcs ? function (node) {
            return pure_funcs.indexOf(node.expression.print_to_string()) < 0;
        } : return_true;
    }
    var top_retain = this.options["top_retain"];
    if (top_retain instanceof RegExp) {
        this.top_retain = function (def) {
            return top_retain.test(def.name);
        };
    } else if (typeof top_retain == "function") {
        this.top_retain = top_retain;
    } else if (top_retain) {
        if (typeof top_retain == "string") {
            top_retain = top_retain.split(/,/);
        }
        this.top_retain = function (def) {
            return top_retain.indexOf(def.name) >= 0;
        };
    }
    var toplevel = this.options["toplevel"];
    this.toplevel = typeof toplevel == "string" ? {
        funcs: /funcs/.test(toplevel),
        vars: /vars/.test(toplevel)
    } : {
        funcs: toplevel,
        vars: toplevel
    };
    var sequences = this.options["sequences"];
    this.sequences_limit = sequences == 1 ? 800 : sequences | 0;
    this.warnings_produced = {};
}

Compressor.prototype = new TreeTransformer;

merge(Compressor.prototype, {
    option: function (key) {
        return this.options[key]
    },
    exposed: function (def) {
        if (def.global) for (var i = 0, len = def.orig.length; i < len; i++)
            if (!this.toplevel[def.orig[i] instanceof AST_SymbolDefun ? "funcs" : "vars"])
                return true;
        return false;
    },
    compress: function (node) {
        if (this.option("expression")) {
            node.process_expression(true);
        }
        var passes = +this.options.passes || 1;
        var last_count = 1 / 0;
        for (var pass = 0; pass < passes; pass++) {
            if (pass > 0 || this.option("reduce_vars"))
                node.reset_opt_flags(this, true);
            node = node.transform(this);
            if (passes > 1) {
                var count = 0;
                node.walk(new TreeWalker(function () {
                    count++;
                }));
                this.info("pass " + pass + ": last_count: " + last_count + ", count: " + count);
                if (count >= last_count) break;
                last_count = count;
            }
        }
        if (this.option("expression")) {
            node.process_expression(false);
        }
        return node;
    },
    info: function () {
        if (this.options.warnings == "verbose") {
            AST_Node.warn.apply(AST_Node, arguments);
        }
    },
    warn: function (text, props) {
        if (this.options.warnings) {
            // only emit unique warnings
            var message = string_template(text, props);
            if (!(message in this.warnings_produced)) {
                this.warnings_produced[message] = true;
                AST_Node.warn.apply(AST_Node, arguments);
            }
        }
    },
    clear_warnings: function () {
        this.warnings_produced = {};
    },
    before: function (node, descend, in_list) {
        if (node._squeezed) return node;
        var was_scope = false;
        if (node instanceof AST_Scope) {
            node = node.hoist_declarations(this);
            was_scope = true;
        }
        // Before https://github.com/mishoo/UglifyJS2/pull/1602 AST_Node.optimize()
        // would call AST_Node.transform() if a different instance of AST_Node is
        // produced after OPT().
        // This corrupts TreeWalker.stack, which cause AST look-ups to malfunction.
        // Migrate and defer all children's AST_Node.transform() to below, which
        // will now happen after this parent AST_Node has been properly substituted
        // thus gives a consistent AST snapshot.
        descend(node, this);
        // Existing code relies on how AST_Node.optimize() worked, and omitting the
        // following replacement call would result in degraded efficiency of both
        // output and performance.
        descend(node, this);
        var opt = node.optimize(this);
        if (was_scope && opt instanceof AST_Scope) {
            opt.drop_unused(this);
            descend(opt, this);
        }
        if (opt === node) opt._squeezed = true;
        return opt;
    }
});

(function () {

    function OPT(node, optimizer) {
        node.DEFMETHOD("optimize", function (compressor) {
            var self = this;
            if (self._optimized) return self;
            if (compressor.has_directive("use asm")) return self;
            var opt = optimizer(self, compressor);
            opt._optimized = true;
            return opt;
        });
    }

    OPT(AST_Node, function (self, compressor) {
        return self;
    });

    AST_Node.DEFMETHOD("equivalent_to", function (node) {
        return this.TYPE == node.TYPE && this.print_to_string() == node.print_to_string();
    });

    AST_Scope.DEFMETHOD("process_expression", function (insert, compressor) {
        var self = this;
        var tt = new TreeTransformer(function (node) {
            if (insert && node instanceof AST_SimpleStatement) {
                return make_node(AST_Return, node, {
                    value: node.body
                });
            }
            if (!insert && node instanceof AST_Return) {
                if (compressor) {
                    var value = node.value && node.value.drop_side_effect_free(compressor, true);
                    return value ? make_node(AST_SimpleStatement, node, {
                        body: value
                    }) : make_node(AST_EmptyStatement, node);
                }
                return make_node(AST_SimpleStatement, node, {
                    body: node.value || make_node(AST_UnaryPrefix, node, {
                        operator: "void",
                        expression: make_node(AST_Number, node, {
                            value: 0
                        })
                    })
                });
            }
            if (node instanceof AST_Lambda && node !== self) {
                return node;
            }
            if (node instanceof AST_Block) {
                var index = node.body.length - 1;
                if (index >= 0) {
                    node.body[index] = node.body[index].transform(tt);
                }
            }
            if (node instanceof AST_If) {
                node.body = node.body.transform(tt);
                if (node.alternative) {
                    node.alternative = node.alternative.transform(tt);
                }
            }
            if (node instanceof AST_With) {
                node.body = node.body.transform(tt);
            }
            return node;
        });
        self.transform(tt);
    });

    AST_Node.DEFMETHOD("reset_opt_flags", function (compressor, rescan) {
        var reduce_vars = rescan && compressor.option("reduce_vars");
        var safe_ids = Object.create(null);
        var suppressor = new TreeWalker(function (node) {
            if (!(node instanceof AST_Symbol)) return;
            var d = node.definition();
            if (!d) return;
            if (node instanceof AST_SymbolRef) d.references.push(node);
            d.fixed = false;
        });
        var tw = new TreeWalker(function (node, descend) {
            node._squeezed = false;
            node._optimized = false;
            if (reduce_vars) {
                if (node instanceof AST_Toplevel) node.globals.each(reset_def);
                if (node instanceof AST_Scope) node.variables.each(reset_def);
                if (node instanceof AST_SymbolRef) {
                    var d = node.definition();
                    d.references.push(node);
                    if (d.fixed === undefined || !safe_to_read(d)
                        || is_modified(node, 0, is_immutable(node.fixed_value()))) {
                        d.fixed = false;
                    } else {
                        var parent = tw.parent();
                        if (parent instanceof AST_Assign && parent.operator == "=" && node === parent.right
                            || parent instanceof AST_Call && node !== parent.expression
                            || parent instanceof AST_Return && node === parent.value && node.scope !== d.scope
                            || parent instanceof AST_VarDef && node === parent.value) {
                            d.escaped = true;
                        }
                    }
                }
                if (node instanceof AST_SymbolCatch) {
                    node.definition().fixed = false;
                }
                if (node instanceof AST_VarDef) {
                    var d = node.name.definition();
                    if (d.fixed === undefined || safe_to_assign(d, node.value)) {
                        if (node.value) {
                            d.fixed = function () {
                                return node.value;
                            };
                            mark(d, false);
                            descend();
                        } else {
                            d.fixed = null;
                        }
                        mark(d, true);
                        return true;
                    } else if (node.value) {
                        d.fixed = false;
                    }
                }
                if (node instanceof AST_Assign
                    && node.operator == "="
                    && node.left instanceof AST_SymbolRef) {
                    var d = node.left.definition();
                    if (safe_to_assign(d, node.right)) {
                        d.references.push(node.left);
                        d.fixed = function () {
                            return node.right;
                        };
                        mark(d, false);
                        node.right.walk(tw);
                        mark(d, true);
                        return true;
                    }
                }
                if (node instanceof AST_Defun) {
                    var d = node.name.definition();
                    if (compressor.exposed(d) || safe_to_read(d)) {
                        d.fixed = false;
                    } else {
                        d.fixed = node;
                        mark(d, true);
                    }
                    var save_ids = safe_ids;
                    safe_ids = Object.create(null);
                    descend();
                    safe_ids = save_ids;
                    return true;
                }
                if (node instanceof AST_Function) {
                    push();
                    var iife;
                    if (!node.name
                        && (iife = tw.parent()) instanceof AST_Call
                        && iife.expression === node) {
                        // Virtually turn IIFE parameters into variable definitions:
                        //   (function(a,b) {...})(c,d) => (function() {var a=c,b=d; ...})()
                        // So existing transformation rules can work on them.
                        node.argnames.forEach(function (arg, i) {
                            var d = arg.definition();
                            if (!node.uses_arguments && d.fixed === undefined) {
                                d.fixed = function () {
                                    return iife.args[i] || make_node(AST_Undefined, iife);
                                };
                                mark(d, true);
                            } else {
                                d.fixed = false;
                            }
                        });
                    }
                    descend();
                    pop();
                    return true;
                }
                if (node instanceof AST_Accessor) {
                    var save_ids = safe_ids;
                    safe_ids = Object.create(null);
                    descend();
                    safe_ids = save_ids;
                    return true;
                }
                if (node instanceof AST_Binary
                    && (node.operator == "&&" || node.operator == "||")) {
                    node.left.walk(tw);
                    push();
                    node.right.walk(tw);
                    pop();
                    return true;
                }
                if (node instanceof AST_Conditional) {
                    node.condition.walk(tw);
                    push();
                    node.consequent.walk(tw);
                    pop();
                    push();
                    node.alternative.walk(tw);
                    pop();
                    return true;
                }
                if (node instanceof AST_If) {
                    node.condition.walk(tw);
                    push();
                    node.body.walk(tw);
                    pop();
                    if (node.alternative) {
                        push();
                        node.alternative.walk(tw);
                        pop();
                    }
                    return true;
                }
                if (node instanceof AST_DWLoop) {
                    push();
                    node.condition.walk(tw);
                    node.body.walk(tw);
                    pop();
                    return true;
                }
                if (node instanceof AST_LabeledStatement) {
                    push();
                    node.body.walk(tw);
                    pop();
                    return true;
                }
                if (node instanceof AST_For) {
                    if (node.init) node.init.walk(tw);
                    if (node.condition) {
                        push();
                        node.condition.walk(tw);
                        pop();
                    }
                    push();
                    node.body.walk(tw);
                    pop();
                    if (node.step) {
                        push();
                        node.step.walk(tw);
                        pop();
                    }
                    return true;
                }
                if (node instanceof AST_ForIn) {
                    node.init.walk(suppressor);
                    node.object.walk(tw);
                    push();
                    node.body.walk(tw);
                    pop();
                    return true;
                }
                if (node instanceof AST_Try) {
                    push();
                    walk_body(node, tw);
                    pop();
                    if (node.bcatch) {
                        push();
                        node.bcatch.walk(tw);
                        pop();
                    }
                    if (node.bfinally) node.bfinally.walk(tw);
                    return true;
                }
                if (node instanceof AST_SwitchBranch) {
                    push();
                    descend();
                    pop();
                    return true;
                }
            }
        });
        this.walk(tw);

        function mark(def, safe) {
            safe_ids[def.id] = safe;
        }

        function safe_to_read(def) {
            if (safe_ids[def.id]) {
                if (def.fixed == null) {
                    var orig = def.orig[0];
                    if (orig instanceof AST_SymbolFunarg || orig.name == "arguments") return false;
                    def.fixed = make_node(AST_Undefined, orig);
                }
                return true;
            }
        }

        function safe_to_assign(def, value) {
            if (!HOP(safe_ids, def.id)) return false;
            if (!safe_to_read(def)) return false;
            if (def.fixed === false) return false;
            if (def.fixed != null && (!value || def.references.length > 0)) return false;
            return !def.orig.some(function (sym) {
                return sym instanceof AST_SymbolDefun
                    || sym instanceof AST_SymbolLambda;
            });
        }

        function push() {
            safe_ids = Object.create(safe_ids);
        }

        function pop() {
            safe_ids = Object.getPrototypeOf(safe_ids);
        }

        function reset_def(def) {
            def.escaped = false;
            if (def.scope.uses_eval) {
                def.fixed = false;
            } else if (!compressor.exposed(def)) {
                def.fixed = undefined;
            } else {
                def.fixed = false;
            }
            def.references = [];
            def.should_replace = undefined;
        }

        function is_immutable(value) {
            return value && value.is_constant() || value instanceof AST_Lambda;
        }

        function is_modified(node, level, immutable) {
            var parent = tw.parent(level);
            if (is_lhs(node, parent)
                || !immutable && parent instanceof AST_Call && parent.expression === node) {
                return true;
            } else if (parent instanceof AST_PropAccess && parent.expression === node) {
                return !immutable && is_modified(parent, level + 1);
            }
        }
    });

    AST_SymbolRef.DEFMETHOD("fixed_value", function () {
        var fixed = this.definition().fixed;
        if (!fixed || fixed instanceof AST_Node) return fixed;
        return fixed();
    });

    AST_SymbolRef.DEFMETHOD("is_immutable", function () {
        var orig = this.definition().orig;
        return orig.length == 1 && orig[0] instanceof AST_SymbolLambda;
    });

    function is_lhs_read_only(lhs) {
        if (lhs instanceof AST_SymbolRef) return lhs.definition().orig[0] instanceof AST_SymbolLambda;
        if (lhs instanceof AST_PropAccess) {
            lhs = lhs.expression;
            if (lhs instanceof AST_SymbolRef) {
                if (lhs.is_immutable()) return false;
                lhs = lhs.fixed_value();
            }
            if (!lhs) return true;
            if (lhs instanceof AST_RegExp) return false;
            if (lhs instanceof AST_Constant) return true;
            return is_lhs_read_only(lhs);
        }
        return false;
    }

    function find_variable(compressor, name) {
        var scope, i = 0;
        while (scope = compressor.parent(i++)) {
            if (scope instanceof AST_Scope) break;
            if (scope instanceof AST_Catch) {
                scope = scope.argname.definition().scope;
                break;
            }
        }
        return scope.find_variable(name);
    }

    function make_node(ctor, orig, props) {
        if (!props) props = {};
        if (orig) {
            if (!props.start) props.start = orig.start;
            if (!props.end) props.end = orig.end;
        }
        return new ctor(props);
    };

    function make_sequence(orig, expressions) {
        if (expressions.length == 1) return expressions[0];
        return make_node(AST_Sequence, orig, {
            expressions: expressions
        });
    }

    function make_node_from_constant(val, orig) {
        switch (typeof val) {
            case "string":
                return make_node(AST_String, orig, {
                    value: val
                });
            case "number":
                if (isNaN(val)) return make_node(AST_NaN, orig);
                if (isFinite(val)) {
                    return 1 / val < 0 ? make_node(AST_UnaryPrefix, orig, {
                        operator: "-",
                        expression: make_node(AST_Number, orig, {value: -val})
                    }) : make_node(AST_Number, orig, {value: val});
                }
                return val < 0 ? make_node(AST_UnaryPrefix, orig, {
                    operator: "-",
                    expression: make_node(AST_Infinity, orig)
                }) : make_node(AST_Infinity, orig);
            case "boolean":
                return make_node(val ? AST_True : AST_False, orig);
            case "undefined":
                return make_node(AST_Undefined, orig);
            default:
                if (val === null) {
                    return make_node(AST_Null, orig, {value: null});
                }
                if (val instanceof RegExp) {
                    return make_node(AST_RegExp, orig, {value: val});
                }
                throw new Error(string_template("Can't handle constant of type: {type}", {
                    type: typeof val
                }));
        }
    };

    // we shouldn't compress (1,func)(something) to
    // func(something) because that changes the meaning of
    // the func (becomes lexical instead of global).
    function maintain_this_binding(parent, orig, val) {
        if (parent instanceof AST_UnaryPrefix && parent.operator == "delete"
            || parent instanceof AST_Call && parent.expression === orig
            && (val instanceof AST_PropAccess || val instanceof AST_SymbolRef && val.name == "eval")) {
            return make_sequence(orig, [make_node(AST_Number, orig, {value: 0}), val]);
        }
        return val;
    }

    function merge_sequence(array, node) {
        if (node instanceof AST_Sequence) {
            array.push.apply(array, node.expressions);
        } else {
            array.push(node);
        }
    }

    function as_statement_array(thing) {
        if (thing === null) return [];
        if (thing instanceof AST_BlockStatement) return thing.body;
        if (thing instanceof AST_EmptyStatement) return [];
        if (thing instanceof AST_Statement) return [thing];
        throw new Error("Can't convert thing to statement array");
    };

    function is_empty(thing) {
        if (thing === null) {
            return true;
        }

        if (thing instanceof AST_EmptyStatement) {
            return true;
        }

        if (thing instanceof AST_BlockStatement) {
            return thing.body.length == 0;
        }
        return false;
    }

    function loop_body(x) {
        if (x instanceof AST_Switch) {
            return x;
        }
        if (x instanceof AST_For || x instanceof AST_ForIn || x instanceof AST_DWLoop) {
            return (x.body instanceof AST_BlockStatement ? x.body : x);
        }
        return x;
    };

    function is_iife_call(node) {
        if (node instanceof AST_Call && !(node instanceof AST_New)) {
            return node.expression instanceof AST_Function || is_iife_call(node.expression);
        }
        return false;
    }

    function is_undeclared_ref(node) {
        return node instanceof AST_SymbolRef && node.definition().undeclared;
    }

    var global_names = makePredicate("Array Boolean console Error Function Math Number RegExp Object String");
    AST_SymbolRef.DEFMETHOD("is_declared", function (compressor) {
        return !this.definition().undeclared
            || compressor.option("unsafe") && global_names(this.name);
    });

    function tighten_body(statements, compressor) {
        var CHANGED, max_iter = 10;
        do {
            CHANGED = false;
            eliminate_spurious_blocks(statements);
            if (compressor.option("dead_code")) {
                eliminate_dead_code(statements, compressor);
            }
            if (compressor.option("if_return")) {
                handle_if_return(statements, compressor);
            }
            if (compressor.sequences_limit > 0) {
                sequencesize(statements, compressor);
            }
            if (compressor.option("join_vars")) {
                join_consecutive_vars(statements, compressor);
            }
            if (compressor.option("collapse_vars")) {
                collapse(statements, compressor);
            }
        } while (CHANGED && max_iter-- > 0);

        // Search from right to left for assignment-like expressions:
        // - `var a = x;`
        // - `a = x;`
        // - `++a`
        // For each candidate, scan from left to right for first usage, then try
        // to fold assignment into the site for compression.
        // Will not attempt to collapse assignments into or past code blocks
        // which are not sequentially executed, e.g. loops and conditionals.
        function collapse(statements, compressor) {
            var scope = compressor.find_parent(AST_Scope);
            if (scope.uses_eval || scope.uses_with) return statements;
            var candidates = [];
            var stat_index = statements.length;
            while (--stat_index >= 0) {
                // Treat parameters as collapsible in IIFE, i.e.
                //   function(a, b){ ... }(x());
                // would be translated into equivalent assignments:
                //   var a = x(), b = undefined;
                if (stat_index == 0 && compressor.option("unused")) extract_args();
                // Find collapsible assignments
                extract_candidates(statements[stat_index]);
                while (candidates.length > 0) {
                    var candidate = candidates.pop();
                    var lhs = get_lhs(candidate);
                    if (!lhs || is_lhs_read_only(lhs)) continue;
                    // Locate symbols which may execute code outside of scanning range
                    var lvalues = get_lvalues(candidate);
                    if (lhs instanceof AST_SymbolRef) lvalues[lhs.name] = false;
                    var side_effects = value_has_side_effects(candidate);
                    var hit = candidate.name instanceof AST_SymbolFunarg;
                    var abort = false, replaced = false;
                    var tt = new TreeTransformer(function (node, descend) {
                        if (abort) return node;
                        // Skip nodes before `candidate` as quickly as possible
                        if (!hit) {
                            if (node === candidate) {
                                hit = true;
                                return node;
                            }
                            return;
                        }
                        // Stop immediately if these node types are encountered
                        var parent = tt.parent();
                        if (node instanceof AST_Assign && node.operator != "=" && lhs.equivalent_to(node.left)
                            || node instanceof AST_Call && lhs instanceof AST_PropAccess && lhs.equivalent_to(node.expression)
                            || node instanceof AST_Debugger
                            || node instanceof AST_IterationStatement && !(node instanceof AST_For)
                            || node instanceof AST_SymbolRef && !node.is_declared(compressor)
                            || node instanceof AST_Try
                            || node instanceof AST_With
                            || parent instanceof AST_For && node !== parent.init) {
                            abort = true;
                            return node;
                        }
                        // Replace variable with assignment when found
                        if (!(node instanceof AST_SymbolDeclaration)
                            && !is_lhs(node, parent)
                            && lhs.equivalent_to(node)) {
                            CHANGED = replaced = abort = true;
                            compressor.info("Collapsing {name} [{file}:{line},{col}]", {
                                name: node.print_to_string(),
                                file: node.start.file,
                                line: node.start.line,
                                col: node.start.col
                            });
                            if (candidate instanceof AST_UnaryPostfix) {
                                return make_node(AST_UnaryPrefix, candidate, candidate);
                            }
                            if (candidate instanceof AST_VarDef) {
                                var def = candidate.name.definition();
                                if (def.references.length == 1 && !compressor.exposed(def)) {
                                    return maintain_this_binding(parent, node, candidate.value);
                                }
                                return make_node(AST_Assign, candidate, {
                                    operator: "=",
                                    left: make_node(AST_SymbolRef, candidate.name, candidate.name),
                                    right: candidate.value
                                });
                            }
                            candidate.write_only = false;
                            return candidate;
                        }
                        // These node types have child nodes that execute sequentially,
                        // but are otherwise not safe to scan into or beyond them.
                        var sym;
                        if (node instanceof AST_Call
                            || node instanceof AST_Exit
                            || node instanceof AST_PropAccess
                            || node instanceof AST_SymbolRef
                            && (lvalues[node.name]
                            || side_effects && !references_in_scope(node.definition()))
                            || (sym = lhs_or_def(node)) && get_symbol(sym).name in lvalues
                            || parent instanceof AST_Binary
                            && (parent.operator == "&&" || parent.operator == "||")
                            || parent instanceof AST_Case
                            || parent instanceof AST_Conditional
                            || parent instanceof AST_For
                            || parent instanceof AST_If) {
                            if (!(node instanceof AST_Scope)) descend(node, tt);
                            abort = true;
                            return node;
                        }
                        // Skip (non-executed) functions and (leading) default case in switch statements
                        if (node instanceof AST_Default || node instanceof AST_Scope) return node;
                    });
                    for (var i = stat_index; !abort && i < statements.length; i++) {
                        statements[i].transform(tt);
                    }
                    if (replaced && !remove_candidate(candidate)) statements.splice(stat_index, 1);
                }
            }

            function extract_args() {
                var iife, fn = compressor.self();
                if (fn instanceof AST_Function
                    && !fn.name
                    && !fn.uses_arguments
                    && !fn.uses_eval
                    && (iife = compressor.parent()) instanceof AST_Call
                    && iife.expression === fn) {
                    var names = Object.create(null);
                    for (var i = fn.argnames.length; --i >= 0;) {
                        var sym = fn.argnames[i];
                        if (sym.name in names) continue;
                        names[sym.name] = true;
                        var arg = iife.args[i];
                        if (!arg) arg = make_node(AST_Undefined, sym);
                        else {
                            var tw = new TreeWalker(function (node) {
                                if (!arg) return true;
                                if (node instanceof AST_SymbolRef && fn.variables.has(node.name)) {
                                    var s = node.definition().scope;
                                    if (s !== scope) while (s = s.parent_scope) {
                                        if (s === scope) return true;
                                    }
                                    arg = null;
                                }
                                if (node instanceof AST_This && !tw.find_parent(AST_Scope)) {
                                    arg = null;
                                    return true;
                                }
                            });
                            arg.walk(tw);
                        }
                        if (arg) candidates.unshift(make_node(AST_VarDef, sym, {
                            name: sym,
                            value: arg
                        }));
                    }
                }
            }

            function extract_candidates(expr) {
                if (expr instanceof AST_Assign && !expr.left.has_side_effects(compressor)
                    || expr instanceof AST_Unary && (expr.operator == "++" || expr.operator == "--")) {
                    candidates.push(expr);
                } else if (expr instanceof AST_Sequence) {
                    expr.expressions.forEach(extract_candidates);
                } else if (expr instanceof AST_Definitions) {
                    expr.definitions.forEach(function (var_def) {
                        if (var_def.value) candidates.push(var_def);
                    });
                } else if (expr instanceof AST_SimpleStatement) {
                    extract_candidates(expr.body);
                } else if (expr instanceof AST_For && expr.init) {
                    extract_candidates(expr.init);
                }
            }

            function get_lhs(expr) {
                if (expr instanceof AST_VarDef) {
                    var def = expr.name.definition();
                    if (def.orig.length > 1 && !(expr.name instanceof AST_SymbolFunarg)
                        || def.references.length == 1 && !compressor.exposed(def)) {
                        return make_node(AST_SymbolRef, expr.name, expr.name);
                    }
                } else {
                    return expr[expr instanceof AST_Assign ? "left" : "expression"];
                }
            }

            function get_symbol(node) {
                while (node instanceof AST_PropAccess) node = node.expression;
                return node;
            }

            function get_lvalues(expr) {
                var lvalues = Object.create(null);
                if (expr instanceof AST_Unary) {
                    return lvalues;
                }
                var scope;
                var tw = new TreeWalker(function (node, descend) {
                    if (node instanceof AST_Scope) {
                        var save_scope = scope;
                        descend();
                        scope = save_scope;
                        return true;
                    }
                    if (node instanceof AST_SymbolRef || node instanceof AST_PropAccess) {
                        var sym = get_symbol(node);
                        if (sym instanceof AST_SymbolRef) {
                            lvalues[sym.name] = lvalues[sym.name] || is_lhs(node, tw.parent());
                        }
                    }
                });
                expr[expr instanceof AST_Assign ? "right" : "value"].walk(tw);
                return lvalues;
            }

            function lhs_or_def(node) {
                if (node instanceof AST_VarDef) return node.value && node.name;
                return is_lhs(node.left, node);
            }

            function remove_candidate(expr) {
                if (expr.name instanceof AST_SymbolFunarg) {
                    var index = compressor.self().argnames.indexOf(expr.name);
                    var args = compressor.parent().args;
                    if (args[index]) args[index] = make_node(AST_Number, args[index], {
                        value: 0
                    });
                    return true;
                }
                var found = false;
                return statements[stat_index].transform(new TreeTransformer(function (node, descend, in_list) {
                    if (found) return node;
                    if (node === expr) {
                        found = true;
                        if (node instanceof AST_VarDef) {
                            remove(node.name.definition().orig, node.name);
                        }
                        return in_list ? MAP.skip : null;
                    }
                }, function (node) {
                    if (node instanceof AST_Sequence) switch (node.expressions.length) {
                        case 0:
                            return null;
                        case 1:
                            return node.expressions[0];
                    }
                    if (node instanceof AST_Definitions && node.definitions.length == 0
                        || node instanceof AST_SimpleStatement && !node.body) {
                        return null;
                    }
                }));
            }

            function value_has_side_effects(expr) {
                if (expr instanceof AST_Unary) {
                    return false;
                }
                return expr[expr instanceof AST_Assign ? "right" : "value"].has_side_effects(compressor);
            }

            function references_in_scope(def) {
                if (def.orig.length == 1 && def.orig[0] instanceof AST_SymbolDefun) {
                    return true;
                }
                if (def.scope !== scope) {
                    return false;
                }
                return def.references.every(function (ref) {
                    return ref.scope === scope;
                });
            }
        }

        function eliminate_spurious_blocks(statements) {
            var seen_dirs = [];
            for (var i = 0; i < statements.length;) {
                var stat = statements[i];
                if (stat instanceof AST_BlockStatement) {
                    CHANGED = true;
                    eliminate_spurious_blocks(stat.body);
                    [].splice.apply(statements, [i, 1].concat(stat.body));
                    i += stat.body.length;
                } else if (stat instanceof AST_EmptyStatement) {
                    CHANGED = true;
                    statements.splice(i, 1);
                } else if (stat instanceof AST_Directive) {
                    if (seen_dirs.indexOf(stat.value) < 0) {
                        i++;
                        seen_dirs.push(stat.value);
                    } else {
                        CHANGED = true;
                        statements.splice(i, 1);
                    }
                } else i++;
            }
        }

        function handle_if_return(statements, compressor) {
            var self = compressor.self();
            var multiple_if_returns = has_multiple_if_returns(statements);
            var in_lambda = self instanceof AST_Lambda;
            for (var i = statements.length; --i >= 0;) {
                var stat = statements[i];
                var next = statements[i + 1];

                if (in_lambda && stat instanceof AST_Return && !stat.value && !next) {
                    CHANGED = true;
                    statements.length--;
                    continue;
                }

                if (stat instanceof AST_If) {
                    var ab = aborts(stat.body);
                    if (can_merge_flow(ab)) {
                        if (ab.label) {
                            remove(ab.label.thedef.references, ab);
                        }
                        CHANGED = true;
                        stat = stat.clone();
                        stat.condition = stat.condition.negate(compressor);
                        var body = as_statement_array_with_return(stat.body, ab);
                        stat.body = make_node(AST_BlockStatement, stat, {
                            body: as_statement_array(stat.alternative).concat(extract_functions())
                        });
                        stat.alternative = make_node(AST_BlockStatement, stat, {
                            body: body
                        });
                        statements[i] = stat.transform(compressor);
                        continue;
                    }

                    var ab = aborts(stat.alternative);
                    if (can_merge_flow(ab)) {
                        if (ab.label) {
                            remove(ab.label.thedef.references, ab);
                        }
                        CHANGED = true;
                        stat = stat.clone();
                        stat.body = make_node(AST_BlockStatement, stat.body, {
                            body: as_statement_array(stat.body).concat(extract_functions())
                        });
                        var body = as_statement_array_with_return(stat.alternative, ab);
                        stat.alternative = make_node(AST_BlockStatement, stat.alternative, {
                            body: body
                        });
                        statements[i] = stat.transform(compressor);
                        continue;
                    }
                }

                if (stat instanceof AST_If && stat.body instanceof AST_Return) {
                    var value = stat.body.value;
                    //---
                    // pretty silly case, but:
                    // if (foo()) return; return; ==> foo(); return;
                    if (!value && !stat.alternative
                        && (in_lambda && !next || next instanceof AST_Return && !next.value)) {
                        CHANGED = true;
                        statements[i] = make_node(AST_SimpleStatement, stat.condition, {
                            body: stat.condition
                        });
                        continue;
                    }
                    //---
                    // if (foo()) return x; return y; ==> return foo() ? x : y;
                    if (value && !stat.alternative && next instanceof AST_Return && next.value) {
                        CHANGED = true;
                        stat = stat.clone();
                        stat.alternative = next;
                        statements.splice(i, 2, stat.transform(compressor));
                        continue;
                    }
                    //---
                    // if (foo()) return x; [ return ; ] ==> return foo() ? x : undefined;
                    if (multiple_if_returns && in_lambda && value && !stat.alternative
                        && (!next || next instanceof AST_Return)) {
                        CHANGED = true;
                        stat = stat.clone();
                        stat.alternative = next || make_node(AST_Return, stat, {
                                value: null
                            });
                        statements.splice(i, next ? 2 : 1, stat.transform(compressor));
                        continue;
                    }
                    //---
                    // if (a) return b; if (c) return d; e; ==> return a ? b : c ? d : void e;
                    //
                    // if sequences is not enabled, this can lead to an endless loop (issue #866).
                    // however, with sequences on this helps producing slightly better output for
                    // the example code.
                    var prev = statements[i - 1];
                    if (compressor.option("sequences") && in_lambda && !stat.alternative
                        && prev instanceof AST_If && prev.body instanceof AST_Return
                        && i + 2 == statements.length && next instanceof AST_SimpleStatement) {
                        CHANGED = true;
                        statements.push(make_node(AST_Return, next, {
                            value: null
                        }).transform(compressor));
                        continue;
                    }
                }
            }

            function has_multiple_if_returns(statements) {
                var n = 0;
                for (var i = statements.length; --i >= 0;) {
                    var stat = statements[i];
                    if (stat instanceof AST_If && stat.body instanceof AST_Return) {
                        if (++n > 1) return true;
                    }
                }
                return false;
            }

            function is_return_void(value) {
                return !value || value instanceof AST_UnaryPrefix && value.operator == "void";
            }

            function can_merge_flow(ab) {
                if (!ab) {
                    return false;
                }

                var lct = ab instanceof AST_LoopControl ? compressor.loopcontrol_target(ab) : null;

                return ab instanceof AST_Return && in_lambda && is_return_void(ab.value)
                    || ab instanceof AST_Continue && self === loop_body(lct)
                    || ab instanceof AST_Break && lct instanceof AST_BlockStatement && self === lct;
            }

            function extract_functions() {
                var tail = statements.slice(i + 1);
                statements.length = i + 1;
                return tail.filter(function (stat) {
                    if (stat instanceof AST_Defun) {
                        statements.push(stat);
                        return false;
                    }
                    return true;
                });
            }

            function as_statement_array_with_return(node, ab) {
                var body = as_statement_array(node).slice(0, -1);
                if (ab.value) {
                    body.push(make_node(AST_SimpleStatement, ab.value, {
                        body: ab.value.expression
                    }));
                }
                return body;
            }
        }

        function eliminate_dead_code(statements, compressor) {
            var has_quit;
            var self = compressor.self();
            for (var i = 0, n = 0, len = statements.length; i < len; i++) {
                var stat = statements[i];
                if (stat instanceof AST_LoopControl) {
                    var lct = compressor.loopcontrol_target(stat);
                    if (stat instanceof AST_Break
                        && !(lct instanceof AST_IterationStatement)
                        && loop_body(lct) === self
                        || stat instanceof AST_Continue
                        && loop_body(lct) === self) {
                        if (stat.label) {
                            remove(stat.label.thedef.references, stat);
                        }
                    } else {
                        statements[n++] = stat;
                    }
                } else {
                    statements[n++] = stat;
                }
                if (aborts(stat)) {
                    has_quit = statements.slice(i + 1);
                    break;
                }
            }
            statements.length = n;
            CHANGED = n != len;
            if (has_quit) {
                has_quit.forEach(function (stat) {
                    extract_declarations_from_unreachable_code(compressor, stat, statements);
                });
            }
        }

        function sequencesize(statements, compressor) {
            if (statements.length < 2) return;
            var seq = [], n = 0;

            function push_seq() {
                if (!seq.length) return;
                var body = make_sequence(seq[0], seq);
                statements[n++] = make_node(AST_SimpleStatement, body, {body: body});
                seq = [];
            }

            for (var i = 0, len = statements.length; i < len; i++) {
                var stat = statements[i];
                if (stat instanceof AST_SimpleStatement) {
                    if (seq.length >= compressor.sequences_limit) push_seq();
                    var body = stat.body;
                    if (seq.length > 0) body = body.drop_side_effect_free(compressor);
                    if (body) merge_sequence(seq, body);
                } else {
                    push_seq();
                    statements[n++] = stat;
                }
            }
            push_seq();
            statements.length = n;
            sequencesize_2(statements, compressor);
            CHANGED = statements.length != len;
        }

        function sequencesize_2(statements, compressor) {
            function cons_seq(right) {
                n--;
                var left = prev.body;
                if (!(left instanceof AST_Sequence)) {
                    left = make_node(AST_Sequence, left, {
                        expressions: [left]
                    });
                }
                merge_sequence(left.expressions, right);
                return left.transform(compressor);
            };
            var n = 0, prev;
            for (var i = 0, len = statements.length; i < len; i++) {
                var stat = statements[i];
                if (prev) {
                    if (stat instanceof AST_For && !(stat.init instanceof AST_Definitions)) {
                        var abort = false;
                        prev.body.walk(new TreeWalker(function (node) {
                            if (abort || node instanceof AST_Scope) return true;
                            if (node instanceof AST_Binary && node.operator == "in") {
                                abort = true;
                                return true;
                            }
                        }));
                        if (!abort) {
                            if (stat.init) stat.init = cons_seq(stat.init);
                            else {
                                stat.init = prev.body.drop_side_effect_free(compressor);
                                n--;
                            }
                        }
                    }
                    else if (stat instanceof AST_If) {
                        stat.condition = cons_seq(stat.condition);
                    }
                    else if (stat instanceof AST_With) {
                        stat.expression = cons_seq(stat.expression);
                    }
                    else if (stat instanceof AST_Exit && stat.value) {
                        stat.value = cons_seq(stat.value);
                    }
                    else if (stat instanceof AST_Exit) {
                        stat.value = cons_seq(make_node(AST_Undefined, stat).transform(compressor));
                    }
                    else if (stat instanceof AST_Switch) {
                        stat.expression = cons_seq(stat.expression);
                    }
                }
                statements[n++] = stat;
                prev = stat instanceof AST_SimpleStatement ? stat : null;
            }
            statements.length = n;
        }

        function join_consecutive_vars(statements, compressor) {
            for (var i = 0, j = -1, len = statements.length; i < len; i++) {
                var stat = statements[i];
                var prev = statements[j];
                if (stat instanceof AST_Definitions && prev && prev.TYPE == stat.TYPE) {
                    prev.definitions = prev.definitions.concat(stat.definitions);
                    CHANGED = true;
                }
                else if (stat instanceof AST_For
                    && prev instanceof AST_Var
                    && (!stat.init || stat.init.TYPE == prev.TYPE)) {
                    CHANGED = true;
                    if (stat.init) {
                        stat.init.definitions = prev.definitions.concat(stat.init.definitions);
                    } else {
                        stat.init = prev;
                    }
                    statements[j] = stat;
                }
                else {
                    statements[++j] = stat;
                }
            }
            statements.length = j + 1;
        };
    }

    function extract_declarations_from_unreachable_code(compressor, stat, target) {
        if (!(stat instanceof AST_Defun)) {
            compressor.warn("Dropping unreachable code [{file}:{line},{col}]", stat.start);
        }
        stat.walk(new TreeWalker(function (node) {
            if (node instanceof AST_Definitions) {
                compressor.warn("Declarations in unreachable code! [{file}:{line},{col}]", node.start);
                node.remove_initializers();
                target.push(node);
                return true;
            }
            if (node instanceof AST_Defun && (node === stat || !compressor.has_directive("use strict"))) {
                target.push(node);
                return true;
            }
            if (node instanceof AST_Scope) {
                return true;
            }
        }));
    };

    function is_undefined(node, compressor) {
        return node.is_undefined
            || node instanceof AST_Undefined
            || node instanceof AST_UnaryPrefix
            && node.operator == "void"
            && !node.expression.has_side_effects(compressor);
    }

    // may_throw_on_access()
    // returns true if this node may be null, undefined or contain `AST_Accessor`
    (function (def) {
        AST_Node.DEFMETHOD("may_throw_on_access", function (compressor) {
            return !compressor.option("pure_getters")
                || this._dot_throw(compressor);
        });

        function is_strict(compressor) {
            return /strict/.test(compressor.option("pure_getters"));
        }

        def(AST_Node, is_strict);
        def(AST_Null, return_true);
        def(AST_Undefined, return_true);
        def(AST_Constant, return_false);
        def(AST_Array, return_false);
        def(AST_Object, function (compressor) {
            if (!is_strict(compressor)) return false;
            for (var i = this.properties.length; --i >= 0;)
                if (this.properties[i].value instanceof AST_Accessor) return true;
            return false;
        });
        def(AST_Function, return_false);
        def(AST_UnaryPostfix, return_false);
        def(AST_UnaryPrefix, function () {
            return this.operator == "void";
        });
        def(AST_Binary, function (compressor) {
            switch (this.operator) {
                case "&&":
                    return this.left._dot_throw(compressor);
                case "||":
                    return this.left._dot_throw(compressor)
                        && this.right._dot_throw(compressor);
                default:
                    return false;
            }
        })
        def(AST_Assign, function (compressor) {
            return this.operator == "="
                && this.right._dot_throw(compressor);
        })
        def(AST_Conditional, function (compressor) {
            return this.consequent._dot_throw(compressor)
                || this.alternative._dot_throw(compressor);
        })
        def(AST_Sequence, function (compressor) {
            return this.expressions[this.expressions.length - 1]._dot_throw(compressor);
        });
        def(AST_SymbolRef, function (compressor) {
            if (this.is_undefined) return true;
            if (!is_strict(compressor)) return false;
            if (is_undeclared_ref(this) && this.is_declared(compressor)) return false;
            if (this.is_immutable()) return false;
            var fixed = this.fixed_value();
            return !fixed || fixed._dot_throw(compressor);
        });
    })(function (node, func) {
        node.DEFMETHOD("_dot_throw", func);
    });

    /* -----[ boolean/negation helpers ]----- */

    // methods to determine whether an expression has a boolean result type
    (function (def) {
        var unary_bool = ["!", "delete"];
        var binary_bool = ["in", "instanceof", "==", "!=", "===", "!==", "<", "<=", ">=", ">"];
        def(AST_Node, return_false);
        def(AST_UnaryPrefix, function () {
            return member(this.operator, unary_bool);
        });
        def(AST_Binary, function () {
            return member(this.operator, binary_bool) ||
                ( (this.operator == "&&" || this.operator == "||") &&
                this.left.is_boolean() && this.right.is_boolean() );
        });
        def(AST_Conditional, function () {
            return this.consequent.is_boolean() && this.alternative.is_boolean();
        });
        def(AST_Assign, function () {
            return this.operator == "=" && this.right.is_boolean();
        });
        def(AST_Sequence, function () {
            return this.expressions[this.expressions.length - 1].is_boolean();
        });
        def(AST_True, return_true);
        def(AST_False, return_true);
    })(function (node, func) {
        node.DEFMETHOD("is_boolean", func);
    });

    // methods to determine if an expression has a numeric result type
    (function (def) {
        def(AST_Node, return_false);
        def(AST_Number, return_true);
        var unary = makePredicate("+ - ~ ++ --");
        def(AST_Unary, function () {
            return unary(this.operator);
        });
        var binary = makePredicate("- * / % & | ^ << >> >>>");
        def(AST_Binary, function (compressor) {
            return binary(this.operator) || this.operator == "+"
                && this.left.is_number(compressor)
                && this.right.is_number(compressor);
        });
        def(AST_Assign, function (compressor) {
            return binary(this.operator.slice(0, -1))
                || this.operator == "=" && this.right.is_number(compressor);
        });
        def(AST_Sequence, function (compressor) {
            return this.expressions[this.expressions.length - 1].is_number(compressor);
        });
        def(AST_Conditional, function (compressor) {
            return this.consequent.is_number(compressor) && this.alternative.is_number(compressor);
        });
    })(function (node, func) {
        node.DEFMETHOD("is_number", func);
    });

    // methods to determine if an expression has a string result type
    (function (def) {
        def(AST_Node, return_false);
        def(AST_String, return_true);
        def(AST_UnaryPrefix, function () {
            return this.operator == "typeof";
        });
        def(AST_Binary, function (compressor) {
            return this.operator == "+" &&
                (this.left.is_string(compressor) || this.right.is_string(compressor));
        });
        def(AST_Assign, function (compressor) {
            return (this.operator == "=" || this.operator == "+=") && this.right.is_string(compressor);
        });
        def(AST_Sequence, function (compressor) {
            return this.expressions[this.expressions.length - 1].is_string(compressor);
        });
        def(AST_Conditional, function (compressor) {
            return this.consequent.is_string(compressor) && this.alternative.is_string(compressor);
        });
    })(function (node, func) {
        node.DEFMETHOD("is_string", func);
    });

    var unary_side_effects = makePredicate("delete ++ --");

    function is_lhs(node, parent) {
        if (parent instanceof AST_Unary && unary_side_effects(parent.operator)) return parent.expression;
        if (parent instanceof AST_Assign && parent.left === node) return node;
    }

    (function (def) {
        AST_Node.DEFMETHOD("resolve_defines", function (compressor) {
            if (!compressor.option("global_defs")) return;
            var def = this._find_defs(compressor, "");
            if (def) {
                var node, parent = this, level = 0;
                do {
                    node = parent;
                    parent = compressor.parent(level++);
                } while (parent instanceof AST_PropAccess && parent.expression === node);
                if (is_lhs(node, parent)) {
                    compressor.warn('global_defs ' + this.print_to_string() + ' redefined [{file}:{line},{col}]', this.start);
                } else {
                    return def;
                }
            }
        });
        function to_node(value, orig) {
            if (value instanceof AST_Node) return make_node(value.CTOR, orig, value);
            if (Array.isArray(value)) return make_node(AST_Array, orig, {
                elements: value.map(function (value) {
                    return to_node(value, orig);
                })
            });
            if (value && typeof value == "object") {
                var props = [];
                for (var key in value) if (HOP(value, key)) {
                    props.push(make_node(AST_ObjectKeyVal, orig, {
                        key: key,
                        value: to_node(value[key], orig)
                    }));
                }
                return make_node(AST_Object, orig, {
                    properties: props
                });
            }
            return make_node_from_constant(value, orig);
        }

        def(AST_Node, noop);
        def(AST_Dot, function (compressor, suffix) {
            return this.expression._find_defs(compressor, "." + this.property + suffix);
        });
        def(AST_SymbolRef, function (compressor, suffix) {
            if (!this.global()) return;
            var name;
            var defines = compressor.option("global_defs");
            if (defines && HOP(defines, (name = this.name + suffix))) {
                var node = to_node(defines[name], this);
                var top = compressor.find_parent(AST_Toplevel);
                node.walk(new TreeWalker(function (node) {
                    if (node instanceof AST_SymbolRef) {
                        node.scope = top;
                        node.thedef = top.def_global(node);
                    }
                }));
                return node;
            }
        });
    })(function (node, func) {
        node.DEFMETHOD("_find_defs", func);
    });

    function best_of_expression(ast1, ast2) {
        return ast1.print_to_string().length >
        ast2.print_to_string().length
            ? ast2 : ast1;
    }

    function best_of_statement(ast1, ast2) {
        return best_of_expression(make_node(AST_SimpleStatement, ast1, {
            body: ast1
        }), make_node(AST_SimpleStatement, ast2, {
            body: ast2
        })).body;
    }

    function best_of(compressor, ast1, ast2) {
        return (first_in_statement(compressor) ? best_of_statement : best_of_expression)(ast1, ast2);
    }

    // methods to evaluate a constant expression
    (function (def) {
        // If the node has been successfully reduced to a constant,
        // then its value is returned; otherwise the element itself
        // is returned.
        // They can be distinguished as constant value is never a
        // descendant of AST_Node.
        AST_Node.DEFMETHOD("evaluate", function (compressor) {
            if (!compressor.option("evaluate")) return this;
            var val = this._eval(compressor);
            return !val || val instanceof RegExp || typeof val != "object" ? val : this;
        });
        var unaryPrefix = makePredicate("! ~ - + void");
        AST_Node.DEFMETHOD("is_constant", function () {
            // Accomodate when compress option evaluate=false
            // as well as the common constant expressions !0 and -1
            if (this instanceof AST_Constant) {
                return !(this instanceof AST_RegExp);
            } else {
                return this instanceof AST_UnaryPrefix
                    && this.expression instanceof AST_Constant
                    && unaryPrefix(this.operator);
            }
        });
        // Obtain the constant value of an expression already known to be constant.
        // Result only valid iff this.is_constant() is true.
        AST_Node.DEFMETHOD("constant_value", function (compressor) {
            // Accomodate when option evaluate=false.
            if (this instanceof AST_Constant && !(this instanceof AST_RegExp)) {
                return this.value;
            }
            // Accomodate the common constant expressions !0 and -1 when option evaluate=false.
            if (this instanceof AST_UnaryPrefix
                && this.expression instanceof AST_Constant) switch (this.operator) {
                case "!":
                    return !this.expression.value;
                case "~":
                    return ~this.expression.value;
                case "-":
                    return -this.expression.value;
                case "+":
                    return +this.expression.value;
                default:
                    throw new Error(string_template("Cannot evaluate unary expression {value}", {
                        value: this.print_to_string()
                    }));
            }
            var result = this.evaluate(compressor);
            if (result !== this) {
                return result;
            }
            throw new Error(string_template("Cannot evaluate constant [{file}:{line},{col}]", this.start));
        });
        def(AST_Statement, function () {
            throw new Error(string_template("Cannot evaluate a statement [{file}:{line},{col}]", this.start));
        });
        def(AST_Lambda, return_this);
        function ev(node, compressor) {
            if (!compressor) throw new Error("Compressor must be passed");

            return node._eval(compressor);
        };
        def(AST_Node, return_this);
        def(AST_Constant, function () {
            return this.getValue();
        });
        def(AST_Array, function (compressor) {
            if (compressor.option("unsafe")) {
                var elements = [];
                for (var i = 0, len = this.elements.length; i < len; i++) {
                    var element = this.elements[i];
                    var value = ev(element, compressor);
                    if (element === value) return this;
                    elements.push(value);
                }
                return elements;
            }
            return this;
        });
        def(AST_Object, function (compressor) {
            if (compressor.option("unsafe")) {
                var val = {};
                for (var i = 0, len = this.properties.length; i < len; i++) {
                    var prop = this.properties[i];
                    var key = prop.key;
                    if (key instanceof AST_Symbol) {
                        key = key.name;
                    } else if (key instanceof AST_Node) {
                        key = ev(key, compressor);
                        if (key === prop.key) return this;
                    }
                    if (typeof Object.prototype[key] === 'function') {
                        return this;
                    }
                    val[key] = ev(prop.value, compressor);
                    if (val[key] === prop.value) return this;
                }
                return val;
            }
            return this;
        });
        def(AST_UnaryPrefix, function (compressor) {
            // Function would be evaluated to an array and so typeof would
            // incorrectly return 'object'. Hence making is a special case.
            if (this.operator == "typeof" && this.expression instanceof AST_Function) {
                return typeof function () {
                };
            }
            var e = ev(this.expression, compressor);
            if (e === this.expression) return this;
            switch (this.operator) {
                case "!":
                    return !e;
                case "typeof":
                    // typeof <RegExp> returns "object" or "function" on different platforms
                    // so cannot evaluate reliably
                    if (e instanceof RegExp) return this;
                    return typeof e;
                case "void":
                    return void e;
                case "~":
                    return ~e;
                case "-":
                    return -e;
                case "+":
                    return +e;
            }
            return this;
        });
        def(AST_Binary, function (compressor) {
            var left = ev(this.left, compressor);
            if (left === this.left) return this;
            var right = ev(this.right, compressor);
            if (right === this.right) return this;
            var result;
            switch (this.operator) {
                case "&&"  :
                    result = left && right;
                    break;
                case "||"  :
                    result = left || right;
                    break;
                case "|"   :
                    result = left | right;
                    break;
                case "&"   :
                    result = left & right;
                    break;
                case "^"   :
                    result = left ^ right;
                    break;
                case "+"   :
                    result = left + right;
                    break;
                case "*"   :
                    result = left * right;
                    break;
                case "/"   :
                    result = left / right;
                    break;
                case "%"   :
                    result = left % right;
                    break;
                case "-"   :
                    result = left - right;
                    break;
                case "<<"  :
                    result = left << right;
                    break;
                case ">>"  :
                    result = left >> right;
                    break;
                case ">>>" :
                    result = left >>> right;
                    break;
                case "=="  :
                    result = left == right;
                    break;
                case "===" :
                    result = left === right;
                    break;
                case "!="  :
                    result = left != right;
                    break;
                case "!==" :
                    result = left !== right;
                    break;
                case "<"   :
                    result = left < right;
                    break;
                case "<="  :
                    result = left <= right;
                    break;
                case ">"   :
                    result = left > right;
                    break;
                case ">="  :
                    result = left >= right;
                    break;
                default:
                    return this;
            }
            if (isNaN(result) && compressor.find_parent(AST_With)) {
                // leave original expression as is
                return this;
            }
            return result;
        });
        def(AST_Conditional, function (compressor) {
            var condition = ev(this.condition, compressor);
            if (condition === this.condition) return this;
            var node = condition ? this.consequent : this.alternative;
            var value = ev(node, compressor);
            return value === node ? this : value;
        });
        def(AST_SymbolRef, function (compressor) {
            if (!compressor.option("reduce_vars")) return this;
            var fixed = this.fixed_value();
            if (!fixed) return this;
            this._eval = return_this;
            var value = ev(fixed, compressor);
            if (value === fixed) {
                delete this._eval;
                return this;
            }
            if (!HOP(fixed, "_eval")) fixed._eval = function () {
                return value;
            };
            if (value && typeof value == "object" && this.definition().escaped) {
                delete this._eval;
                return this;
            }
            this._eval = fixed._eval;
            return value;
        });
        var global_objs = {
            Array: Array,
            Math: Math,
            Number: Number,
            String: String,
        };

        function convert_to_predicate(obj) {
            for (var key in obj) {
                obj[key] = makePredicate(obj[key]);
            }
        }

        var static_values = {
            Math: [
                "E",
                "LN10",
                "LN2",
                "LOG2E",
                "LOG10E",
                "PI",
                "SQRT1_2",
                "SQRT2",
            ],
            Number: [
                "MAX_VALUE",
                "MIN_VALUE",
                "NaN",
                "NEGATIVE_INFINITY",
                "POSITIVE_INFINITY",
            ],
        };
        convert_to_predicate(static_values);
        def(AST_PropAccess, function (compressor) {
            if (compressor.option("unsafe")) {
                var key = this.property;
                if (key instanceof AST_Node) {
                    key = ev(key, compressor);
                    if (key === this.property) return this;
                }
                var exp = this.expression;
                var val;
                if (is_undeclared_ref(exp)) {
                    if (!(static_values[exp.name] || return_false)(key)) return this;
                    val = global_objs[exp.name];
                } else {
                    val = ev(exp, compressor);
                    if (!val || val === exp || !HOP(val, key)) return this;
                }
                return val[key];
            }
            return this;
        });
        var object_fns = [
            "constructor",
            "toString",
            "valueOf",
        ];
        var native_fns = {
            Array: [
                "indexOf",
                "join",
                "lastIndexOf",
                "slice",
            ].concat(object_fns),
            Boolean: object_fns,
            Number: [
                "toExponential",
                "toFixed",
                "toPrecision",
            ].concat(object_fns),
            RegExp: [
                "test",
            ].concat(object_fns),
            String: [
                "charAt",
                "charCodeAt",
                "concat",
                "indexOf",
                "italics",
                "lastIndexOf",
                "match",
                "replace",
                "search",
                "slice",
                "split",
                "substr",
                "substring",
                "trim",
            ].concat(object_fns),
        };
        convert_to_predicate(native_fns);
        var static_fns = {
            Array: [
                "isArray",
            ],
            Math: [
                "abs",
                "acos",
                "asin",
                "atan",
                "ceil",
                "cos",
                "exp",
                "floor",
                "log",
                "round",
                "sin",
                "sqrt",
                "tan",
                "atan2",
                "pow",
                "max",
                "min"
            ],
            Number: [
                "isFinite",
                "isNaN",
            ],
            String: [
                "fromCharCode",
            ],
        };
        convert_to_predicate(static_fns);
        def(AST_Call, function (compressor) {
            var exp = this.expression;
            if (compressor.option("unsafe") && exp instanceof AST_PropAccess) {
                var key = exp.property;
                if (key instanceof AST_Node) {
                    key = ev(key, compressor);
                    if (key === exp.property) return this;
                }
                var val;
                var e = exp.expression;
                if (is_undeclared_ref(e)) {
                    if (!(static_fns[e.name] || return_false)(key)) return this;
                    val = global_objs[e.name];
                } else {
                    val = ev(e, compressor);
                    if (val === e || !(val && native_fns[val.constructor.name] || return_false)(key)) return this;
                }
                var args = [];
                for (var i = 0, len = this.args.length; i < len; i++) {
                    var arg = this.args[i];
                    var value = ev(arg, compressor);
                    if (arg === value) return this;
                    args.push(value);
                }
                return val[key].apply(val, args);
            }
            return this;
        });
        def(AST_New, return_this);
    })(function (node, func) {
        node.DEFMETHOD("_eval", func);
    });

    // method to negate an expression
    (function (def) {
        function basic_negation(exp) {
            return make_node(AST_UnaryPrefix, exp, {
                operator: "!",
                expression: exp
            });
        }

        function best(orig, alt, first_in_statement) {
            var negated = basic_negation(orig);
            if (first_in_statement) {
                var stat = make_node(AST_SimpleStatement, alt, {
                    body: alt
                });
                return best_of_expression(negated, stat) === stat ? alt : negated;
            }
            return best_of_expression(negated, alt);
        }

        def(AST_Node, function () {
            return basic_negation(this);
        });
        def(AST_Statement, function () {
            throw new Error("Cannot negate a statement");
        });
        def(AST_Function, function () {
            return basic_negation(this);
        });
        def(AST_UnaryPrefix, function () {
            if (this.operator == "!")
                return this.expression;
            return basic_negation(this);
        });
        def(AST_Sequence, function (compressor) {
            var expressions = this.expressions.slice();
            expressions.push(expressions.pop().negate(compressor));
            return make_sequence(this, expressions);
        });
        def(AST_Conditional, function (compressor, first_in_statement) {
            var self = this.clone();
            self.consequent = self.consequent.negate(compressor);
            self.alternative = self.alternative.negate(compressor);
            return best(this, self, first_in_statement);
        });
        def(AST_Binary, function (compressor, first_in_statement) {
            var self = this.clone(), op = this.operator;
            if (compressor.option("unsafe_comps")) {
                switch (op) {
                    case "<=" :
                        self.operator = ">";
                        return self;
                    case "<"  :
                        self.operator = ">=";
                        return self;
                    case ">=" :
                        self.operator = "<";
                        return self;
                    case ">"  :
                        self.operator = "<=";
                        return self;
                }
            }
            switch (op) {
                case "==" :
                    self.operator = "!=";
                    return self;
                case "!=" :
                    self.operator = "==";
                    return self;
                case "===":
                    self.operator = "!==";
                    return self;
                case "!==":
                    self.operator = "===";
                    return self;
                case "&&":
                    self.operator = "||";
                    self.left = self.left.negate(compressor, first_in_statement);
                    self.right = self.right.negate(compressor);
                    return best(this, self, first_in_statement);
                case "||":
                    self.operator = "&&";
                    self.left = self.left.negate(compressor, first_in_statement);
                    self.right = self.right.negate(compressor);
                    return best(this, self, first_in_statement);
            }
            return basic_negation(this);
        });
    })(function (node, func) {
        node.DEFMETHOD("negate", function (compressor, first_in_statement) {
            return func.call(this, compressor, first_in_statement);
        });
    });

    AST_Call.DEFMETHOD("has_pure_annotation", function (compressor) {
        if (!compressor.option("side_effects")) return false;
        if (this.pure !== undefined) return this.pure;
        var pure = false;
        var comments, last_comment;
        if (this.start
            && (comments = this.start.comments_before)
            && comments.length
            && /[@#]__PURE__/.test((last_comment = comments[comments.length - 1]).value)) {
            pure = last_comment;
        }
        return this.pure = pure;
    });

    // determine if expression has side effects
    (function (def) {
        def(AST_Node, return_true);

        def(AST_EmptyStatement, return_false);
        def(AST_Constant, return_false);
        def(AST_This, return_false);

        def(AST_Call, function (compressor) {
            if (!this.has_pure_annotation(compressor) && compressor.pure_funcs(this)) return true;
            for (var i = this.args.length; --i >= 0;) {
                if (this.args[i].has_side_effects(compressor))
                    return true;
            }
            return false;
        });

        function any(list, compressor) {
            for (var i = list.length; --i >= 0;)
                if (list[i].has_side_effects(compressor))
                    return true;
            return false;
        }

        def(AST_Block, function (compressor) {
            return any(this.body, compressor);
        });
        def(AST_Switch, function (compressor) {
            return this.expression.has_side_effects(compressor)
                || any(this.body, compressor);
        });
        def(AST_Case, function (compressor) {
            return this.expression.has_side_effects(compressor)
                || any(this.body, compressor);
        });
        def(AST_Try, function (compressor) {
            return any(this.body, compressor)
                || this.bcatch && this.bcatch.has_side_effects(compressor)
                || this.bfinally && this.bfinally.has_side_effects(compressor);
        });
        def(AST_If, function (compressor) {
            return this.condition.has_side_effects(compressor)
                || this.body && this.body.has_side_effects(compressor)
                || this.alternative && this.alternative.has_side_effects(compressor);
        });
        def(AST_LabeledStatement, function (compressor) {
            return this.body.has_side_effects(compressor);
        });
        def(AST_SimpleStatement, function (compressor) {
            return this.body.has_side_effects(compressor);
        });
        def(AST_Defun, return_true);
        def(AST_Function, return_false);
        def(AST_Binary, function (compressor) {
            return this.left.has_side_effects(compressor)
                || this.right.has_side_effects(compressor);
        });
        def(AST_Assign, return_true);
        def(AST_Conditional, function (compressor) {
            return this.condition.has_side_effects(compressor)
                || this.consequent.has_side_effects(compressor)
                || this.alternative.has_side_effects(compressor);
        });
        def(AST_Unary, function (compressor) {
            return unary_side_effects(this.operator)
                || this.expression.has_side_effects(compressor);
        });
        def(AST_SymbolRef, function (compressor) {
            return !this.is_declared(compressor);
        });
        def(AST_SymbolDeclaration, return_false);
        def(AST_Object, function (compressor) {
            return any(this.properties, compressor);
        });
        def(AST_ObjectProperty, function (compressor) {
            return this.value.has_side_effects(compressor);
        });
        def(AST_Array, function (compressor) {
            return any(this.elements, compressor);
        });
        def(AST_Dot, function (compressor) {
            return this.expression.may_throw_on_access(compressor)
                || this.expression.has_side_effects(compressor);
        });
        def(AST_Sub, function (compressor) {
            return this.expression.may_throw_on_access(compressor)
                || this.expression.has_side_effects(compressor)
                || this.property.has_side_effects(compressor);
        });
        def(AST_Sequence, function (compressor) {
            return this.expressions.some(function (expression, index) {
                return expression.has_side_effects(compressor);
            });
        });
    })(function (node, func) {
        node.DEFMETHOD("has_side_effects", func);
    });

    // determine if expression is constant
    (function (def) {
        function all(list) {
            for (var i = list.length; --i >= 0;)
                if (!list[i].is_constant_expression())
                    return false;
            return true;
        }

        def(AST_Node, return_false);
        def(AST_Constant, return_true);
        def(AST_Unary, function () {
            return this.expression.is_constant_expression();
        });
        def(AST_Binary, function () {
            return this.left.is_constant_expression() && this.right.is_constant_expression();
        });
        def(AST_Array, function () {
            return all(this.elements);
        });
        def(AST_Object, function () {
            return all(this.properties);
        });
        def(AST_ObjectProperty, function () {
            return this.value.is_constant_expression();
        });
    })(function (node, func) {
        node.DEFMETHOD("is_constant_expression", func);
    });

    // tell me if a statement aborts
    function aborts(thing) {
        return thing && thing.aborts();
    };
    (function (def) {
        def(AST_Statement, return_null);
        def(AST_Jump, return_this);
        function block_aborts() {
            var n = this.body.length;
            return n > 0 && aborts(this.body[n - 1]);
        };
        def(AST_BlockStatement, block_aborts);
        def(AST_SwitchBranch, block_aborts);
        def(AST_If, function () {
            return this.alternative && aborts(this.body) && aborts(this.alternative) && this;
        });
    })(function (node, func) {
        node.DEFMETHOD("aborts", func);
    });

    /* -----[ optimizers ]----- */

    OPT(AST_Directive, function (self, compressor) {
        if (compressor.has_directive(self.value) !== self) {
            return make_node(AST_EmptyStatement, self);
        }
        return self;
    });

    OPT(AST_Debugger, function (self, compressor) {
        if (compressor.option("drop_debugger"))
            return make_node(AST_EmptyStatement, self);
        return self;
    });

    OPT(AST_LabeledStatement, function (self, compressor) {
        if (self.body instanceof AST_Break
            && compressor.loopcontrol_target(self.body) === self.body) {
            return make_node(AST_EmptyStatement, self);
        }
        return self.label.references.length == 0 ? self.body : self;
    });

    OPT(AST_Block, function (self, compressor) {
        tighten_body(self.body, compressor);
        return self;
    });

    OPT(AST_BlockStatement, function (self, compressor) {
        tighten_body(self.body, compressor);
        switch (self.body.length) {
            case 1:
                return self.body[0];
            case 0:
                return make_node(AST_EmptyStatement, self);
        }
        return self;
    });

    AST_Scope.DEFMETHOD("drop_unused", function (compressor) {
        if (!compressor.option("unused")) return;
        if (compressor.has_directive("use asm")) return;
        var self = this;
        if (self.uses_eval || self.uses_with) return;
        var drop_funcs = !(self instanceof AST_Toplevel) || compressor.toplevel.funcs;
        var drop_vars = !(self instanceof AST_Toplevel) || compressor.toplevel.vars;
        if (!drop_funcs && !drop_vars) return;
        var assign_as_unused = /keep_assign/.test(compressor.option("unused")) ? return_false : function (node) {
            if (node instanceof AST_Assign && (node.write_only || node.operator == "=")) {
                return node.left;
            }
            if (node instanceof AST_Unary && node.write_only) return node.expression;
        };
        var in_use = [];
        var in_use_ids = Object.create(null); // avoid expensive linear scans of in_use
        if (self instanceof AST_Toplevel && compressor.top_retain) {
            self.variables.each(function (def) {
                if (compressor.top_retain(def) && !(def.id in in_use_ids)) {
                    in_use_ids[def.id] = true;
                    in_use.push(def);
                }
            });
        }
        var var_defs_by_id = new Dictionary();
        var initializations = new Dictionary();
        // pass 1: find out which symbols are directly used in
        // this scope (not in nested scopes).
        var scope = this;
        var tw = new TreeWalker(function (node, descend) {
            if (node !== self) {
                if (node instanceof AST_Defun) {
                    if (!drop_funcs && scope === self) {
                        var node_def = node.name.definition();
                        if (!(node_def.id in in_use_ids)) {
                            in_use_ids[node_def.id] = true;
                            in_use.push(node_def);
                        }
                    }
                    initializations.add(node.name.name, node);
                    return true; // don't go in nested scopes
                }
                if (node instanceof AST_Definitions && scope === self) {
                    node.definitions.forEach(function (def) {
                        var node_def = def.name.definition();
                        if (def.name instanceof AST_SymbolVar) {
                            var_defs_by_id.add(node_def.id, def);
                        }
                        if (!drop_vars) {
                            if (!(node_def.id in in_use_ids)) {
                                in_use_ids[node_def.id] = true;
                                in_use.push(node_def);
                            }
                        }
                        if (def.value) {
                            initializations.add(def.name.name, def.value);
                            if (def.value.has_side_effects(compressor)) {
                                def.value.walk(tw);
                            }
                        }
                    });
                    return true;
                }
                if (assign_as_unused(node) instanceof AST_SymbolRef && scope === self) {
                    if (node instanceof AST_Assign) node.right.walk(tw);
                    return true;
                }
                if (node instanceof AST_SymbolRef) {
                    var node_def = node.definition();
                    if (!(node_def.id in in_use_ids)) {
                        in_use_ids[node_def.id] = true;
                        in_use.push(node_def);
                    }
                    return true;
                }
                if (node instanceof AST_Scope) {
                    var save_scope = scope;
                    scope = node;
                    descend();
                    scope = save_scope;
                    return true;
                }
            }
        });
        self.walk(tw);
        // pass 2: for every used symbol we need to walk its
        // initialization code to figure out if it uses other
        // symbols (that may not be in_use).
        for (var i = 0; i < in_use.length; ++i) {
            in_use[i].orig.forEach(function (decl) {
                // undeclared globals will be instanceof AST_SymbolRef
                var init = initializations.get(decl.name);
                if (init) init.forEach(function (init) {
                    var tw = new TreeWalker(function (node) {
                        if (node instanceof AST_SymbolRef) {
                            var node_def = node.definition();
                            if (!(node_def.id in in_use_ids)) {
                                in_use_ids[node_def.id] = true;
                                in_use.push(node_def);
                            }
                        }
                    });
                    init.walk(tw);
                });
            });
        }
        // pass 3: we should drop declarations not in_use
        var tt = new TreeTransformer(
            function before(node, descend, in_list) {
                if (node instanceof AST_Function
                    && node.name
                    && !compressor.option("keep_fnames")) {
                    var def = node.name.definition();
                    // any declarations with same name will overshadow
                    // name of this anonymous function and can therefore
                    // never be used anywhere
                    if (!(def.id in in_use_ids) || def.orig.length > 1)
                        node.name = null;
                }
                if (node instanceof AST_Lambda && !(node instanceof AST_Accessor)) {
                    var trim = !compressor.option("keep_fargs");
                    for (var a = node.argnames, i = a.length; --i >= 0;) {
                        var sym = a[i];
                        if (!(sym.definition().id in in_use_ids)) {
                            sym.__unused = true;
                            if (trim) {
                                a.pop();
                                compressor[sym.unreferenced() ? "warn" : "info"]("Dropping unused function argument {name} [{file}:{line},{col}]", template(sym));
                            }
                        }
                        else {
                            trim = false;
                        }
                    }
                }
                if (drop_funcs && node instanceof AST_Defun && node !== self) {
                    if (!(node.name.definition().id in in_use_ids)) {
                        compressor[node.name.unreferenced() ? "warn" : "info"]("Dropping unused function {name} [{file}:{line},{col}]", template(node.name));
                        return make_node(AST_EmptyStatement, node);
                    }
                    return node;
                }
                if (drop_vars && node instanceof AST_Definitions && !(tt.parent() instanceof AST_ForIn && tt.parent().init === node)) {
                    // place uninitialized names at the start
                    var body = [], head = [], tail = [];
                    // for unused names whose initialization has
                    // side effects, we can cascade the init. code
                    // into the next one, or next statement.
                    var side_effects = [];
                    node.definitions.forEach(function (def) {
                        if (def.value) def.value = def.value.transform(tt);
                        var sym = def.name.definition();
                        if (sym.id in in_use_ids) {
                            if (def.name instanceof AST_SymbolVar) {
                                var var_defs = var_defs_by_id.get(sym.id);
                                if (var_defs.length > 1 && !def.value) {
                                    compressor.warn("Dropping duplicated definition of variable {name} [{file}:{line},{col}]", template(def.name));
                                    remove(var_defs, def);
                                    remove(sym.orig, def.name);
                                    return;
                                }
                            }
                            if (def.value) {
                                if (side_effects.length > 0) {
                                    if (tail.length > 0) {
                                        merge_sequence(side_effects, def.value);
                                        def.value = make_sequence(def.value, side_effects);
                                    } else {
                                        body.push(make_node(AST_SimpleStatement, node, {
                                            body: make_sequence(node, side_effects)
                                        }));
                                    }
                                    side_effects = [];
                                }
                                tail.push(def);
                            } else {
                                head.push(def);
                            }
                        } else if (sym.orig[0] instanceof AST_SymbolCatch) {
                            var value = def.value && def.value.drop_side_effect_free(compressor);
                            if (value) merge_sequence(side_effects, value);
                            def.value = null;
                            head.push(def);
                        } else {
                            var value = def.value && def.value.drop_side_effect_free(compressor);
                            if (value) {
                                compressor.warn("Side effects in initialization of unused variable {name} [{file}:{line},{col}]", template(def.name));
                                merge_sequence(side_effects, value);
                            } else {
                                compressor[def.name.unreferenced() ? "warn" : "info"]("Dropping unused variable {name} [{file}:{line},{col}]", template(def.name));
                            }
                            remove(sym.orig, def.name);
                        }
                    });
                    if (head.length == 0 && tail.length == 1 && tail[0].name instanceof AST_SymbolVar) {
                        var var_defs = var_defs_by_id.get(tail[0].name.definition().id);
                        if (var_defs.length > 1) {
                            var def = tail.pop();
                            compressor.warn("Converting duplicated definition of variable {name} to assignment [{file}:{line},{col}]", template(def.name));
                            remove(var_defs, def);
                            remove(def.name.definition().orig, def.name);
                            side_effects.unshift(make_node(AST_Assign, def, {
                                operator: "=",
                                left: make_node(AST_SymbolRef, def.name, def.name),
                                right: def.value
                            }));
                        }
                    }
                    if (head.length > 0 || tail.length > 0) {
                        node.definitions = head.concat(tail);
                        body.push(node);
                    }
                    if (side_effects.length > 0) {
                        body.push(make_node(AST_SimpleStatement, node, {
                            body: make_sequence(node, side_effects)
                        }));
                    }
                    switch (body.length) {
                        case 0:
                            return in_list ? MAP.skip : make_node(AST_EmptyStatement, node);
                        case 1:
                            return body[0];
                        default:
                            return in_list ? MAP.splice(body) : make_node(AST_BlockStatement, node, {
                                body: body
                            });
                    }
                }
                if (drop_vars) {
                    var def = assign_as_unused(node);
                    if (def instanceof AST_SymbolRef
                        && !((def = def.definition()).id in in_use_ids)
                        && self.variables.get(def.name) === def) {
                        if (node instanceof AST_Assign) {
                            return maintain_this_binding(tt.parent(), node, node.right.transform(tt));
                        }
                        return make_node(AST_Number, node, {
                            value: 0
                        });
                    }
                }
                // certain combination of unused name + side effect leads to:
                //    https://github.com/mishoo/UglifyJS2/issues/44
                //    https://github.com/mishoo/UglifyJS2/issues/1830
                //    https://github.com/mishoo/UglifyJS2/issues/1838
                // that's an invalid AST.
                // We fix it at this stage by moving the `var` outside the `for`.
                if (node instanceof AST_For) {
                    descend(node, this);
                    if (node.init instanceof AST_BlockStatement) {
                        var block = node.init;
                        node.init = block.body.pop();
                        block.body.push(node);
                        return in_list ? MAP.splice(block.body) : block;
                    } else if (node.init instanceof AST_SimpleStatement) {
                        node.init = node.init.body;
                    } else if (is_empty(node.init)) {
                        node.init = null;
                    }
                    return node;
                }
                if (node instanceof AST_LabeledStatement && node.body instanceof AST_For) {
                    descend(node, this);
                    if (node.body instanceof AST_BlockStatement) {
                        var block = node.body;
                        node.body = block.body.pop();
                        block.body.push(node);
                        return in_list ? MAP.splice(block.body) : block;
                    }
                    return node;
                }
                if (node instanceof AST_Scope && node !== self)
                    return node;

                function template(sym) {
                    return {
                        name: sym.name,
                        file: sym.start.file,
                        line: sym.start.line,
                        col: sym.start.col
                    };
                }
            }
        );
        self.transform(tt);
    });

    AST_Scope.DEFMETHOD("hoist_declarations", function (compressor) {
        var self = this;
        if (compressor.has_directive("use asm")) return self;
        var hoist_funs = compressor.option("hoist_funs");
        var hoist_vars = compressor.option("hoist_vars");
        if (hoist_funs || hoist_vars) {
            var dirs = [];
            var hoisted = [];
            var vars = new Dictionary(), vars_found = 0, var_decl = 0;
            // let's count var_decl first, we seem to waste a lot of
            // space if we hoist `var` when there's only one.
            self.walk(new TreeWalker(function (node) {
                if (node instanceof AST_Scope && node !== self)
                    return true;
                if (node instanceof AST_Var) {
                    ++var_decl;
                    return true;
                }
            }));
            hoist_vars = hoist_vars && var_decl > 1;
            var tt = new TreeTransformer(
                function before(node) {
                    if (node !== self) {
                        if (node instanceof AST_Directive) {
                            dirs.push(node);
                            return make_node(AST_EmptyStatement, node);
                        }
                        if (hoist_funs && node instanceof AST_Defun
                            && (tt.parent() === self || !compressor.has_directive("use strict"))) {
                            hoisted.push(node);
                            return make_node(AST_EmptyStatement, node);
                        }
                        if (hoist_vars && node instanceof AST_Var) {
                            node.definitions.forEach(function (def) {
                                vars.set(def.name.name, def);
                                ++vars_found;
                            });
                            var seq = node.to_assignments(compressor);
                            var p = tt.parent();
                            if (p instanceof AST_ForIn && p.init === node) {
                                if (seq == null) {
                                    var def = node.definitions[0].name;
                                    return make_node(AST_SymbolRef, def, def);
                                }
                                return seq;
                            }
                            if (p instanceof AST_For && p.init === node) {
                                return seq;
                            }
                            if (!seq) return make_node(AST_EmptyStatement, node);
                            return make_node(AST_SimpleStatement, node, {
                                body: seq
                            });
                        }
                        if (node instanceof AST_Scope)
                            return node; // to avoid descending in nested scopes
                    }
                }
            );
            self = self.transform(tt);
            if (vars_found > 0) {
                // collect only vars which don't show up in self's arguments list
                var defs = [];
                vars.each(function (def, name) {
                    if (self instanceof AST_Lambda
                        && find_if(function (x) {
                                return x.name == def.name.name
                            },
                            self.argnames)) {
                        vars.del(name);
                    } else {
                        def = def.clone();
                        def.value = null;
                        defs.push(def);
                        vars.set(name, def);
                    }
                });
                if (defs.length > 0) {
                    // try to merge in assignments
                    for (var i = 0; i < self.body.length;) {
                        if (self.body[i] instanceof AST_SimpleStatement) {
                            var expr = self.body[i].body, sym, assign;
                            if (expr instanceof AST_Assign
                                && expr.operator == "="
                                && (sym = expr.left) instanceof AST_Symbol
                                && vars.has(sym.name)) {
                                var def = vars.get(sym.name);
                                if (def.value) break;
                                def.value = expr.right;
                                remove(defs, def);
                                defs.push(def);
                                self.body.splice(i, 1);
                                continue;
                            }
                            if (expr instanceof AST_Sequence
                                && (assign = expr.expressions[0]) instanceof AST_Assign
                                && assign.operator == "="
                                && (sym = assign.left) instanceof AST_Symbol
                                && vars.has(sym.name)) {
                                var def = vars.get(sym.name);
                                if (def.value) break;
                                def.value = assign.right;
                                remove(defs, def);
                                defs.push(def);
                                self.body[i].body = make_sequence(expr, expr.expressions.slice(1));
                                continue;
                            }
                        }
                        if (self.body[i] instanceof AST_EmptyStatement) {
                            self.body.splice(i, 1);
                            continue;
                        }
                        if (self.body[i] instanceof AST_BlockStatement) {
                            var tmp = [i, 1].concat(self.body[i].body);
                            self.body.splice.apply(self.body, tmp);
                            continue;
                        }
                        break;
                    }
                    defs = make_node(AST_Var, self, {
                        definitions: defs
                    });
                    hoisted.push(defs);
                }
                ;
            }
            self.body = dirs.concat(hoisted, self.body);
        }
        return self;
    });

    // drop_side_effect_free()
    // remove side-effect-free parts which only affects return value
    (function (def) {
        // Drop side-effect-free elements from an array of expressions.
        // Returns an array of expressions with side-effects or null
        // if all elements were dropped. Note: original array may be
        // returned if nothing changed.
        function trim(nodes, compressor, first_in_statement) {
            var len = nodes.length;
            if (!len) return null;
            var ret = [], changed = false;
            for (var i = 0; i < len; i++) {
                var node = nodes[i].drop_side_effect_free(compressor, first_in_statement);
                changed |= node !== nodes[i];
                if (node) {
                    merge_sequence(ret, node);
                    first_in_statement = false;
                }
            }
            return changed ? ret.length ? ret : null : nodes;
        }

        def(AST_Node, return_this);
        def(AST_Constant, return_null);
        def(AST_This, return_null);
        def(AST_Call, function (compressor, first_in_statement) {
            if (!this.has_pure_annotation(compressor) && compressor.pure_funcs(this)) {
                if (this.expression instanceof AST_Function
                    && (!this.expression.name || !this.expression.name.definition().references.length)) {
                    var node = this.clone();
                    node.expression.process_expression(false, compressor);
                    return node;
                }
                return this;
            }
            if (this.pure) {
                compressor.warn("Dropping __PURE__ call [{file}:{line},{col}]", this.start);
                this.pure.value = this.pure.value.replace(/[@#]__PURE__/g, ' ');
            }
            var args = trim(this.args, compressor, first_in_statement);
            return args && make_sequence(this, args);
        });
        def(AST_Accessor, return_null);
        def(AST_Function, return_null);
        def(AST_Binary, function (compressor, first_in_statement) {
            var right = this.right.drop_side_effect_free(compressor);
            if (!right) return this.left.drop_side_effect_free(compressor, first_in_statement);
            switch (this.operator) {
                case "&&":
                case "||":
                    if (right === this.right) return this;
                    var node = this.clone();
                    node.right = right;
                    return node;
                default:
                    var left = this.left.drop_side_effect_free(compressor, first_in_statement);
                    if (!left) return this.right.drop_side_effect_free(compressor, first_in_statement);
                    return make_sequence(this, [left, right]);
            }
        });
        def(AST_Assign, function (compressor) {
            this.write_only = !this.left.has_side_effects(compressor);
            return this;
        });
        def(AST_Conditional, function (compressor) {
            var consequent = this.consequent.drop_side_effect_free(compressor);
            var alternative = this.alternative.drop_side_effect_free(compressor);
            if (consequent === this.consequent && alternative === this.alternative) return this;
            if (!consequent) return alternative ? make_node(AST_Binary, this, {
                operator: "||",
                left: this.condition,
                right: alternative
            }) : this.condition.drop_side_effect_free(compressor);
            if (!alternative) return make_node(AST_Binary, this, {
                operator: "&&",
                left: this.condition,
                right: consequent
            });
            var node = this.clone();
            node.consequent = consequent;
            node.alternative = alternative;
            return node;
        });
        def(AST_Unary, function (compressor, first_in_statement) {
            if (unary_side_effects(this.operator)) {
                this.write_only = !this.expression.has_side_effects(compressor);
                return this;
            }
            if (this.operator == "typeof" && this.expression instanceof AST_SymbolRef) return null;
            var expression = this.expression.drop_side_effect_free(compressor, first_in_statement);
            if (first_in_statement
                && this instanceof AST_UnaryPrefix
                && is_iife_call(expression)) {
                if (expression === this.expression && this.operator.length === 1) return this;
                return make_node(AST_UnaryPrefix, this, {
                    operator: this.operator.length === 1 ? this.operator : "!",
                    expression: expression
                });
            }
            return expression;
        });
        def(AST_SymbolRef, function (compressor) {
            return this.is_declared(compressor) ? null : this;
        });
        def(AST_Object, function (compressor, first_in_statement) {
            var values = trim(this.properties, compressor, first_in_statement);
            return values && make_sequence(this, values);
        });
        def(AST_ObjectProperty, function (compressor, first_in_statement) {
            return this.value.drop_side_effect_free(compressor, first_in_statement);
        });
        def(AST_Array, function (compressor, first_in_statement) {
            var values = trim(this.elements, compressor, first_in_statement);
            return values && make_sequence(this, values);
        });
        def(AST_Dot, function (compressor, first_in_statement) {
            if (this.expression.may_throw_on_access(compressor)) return this;
            return this.expression.drop_side_effect_free(compressor, first_in_statement);
        });
        def(AST_Sub, function (compressor, first_in_statement) {
            if (this.expression.may_throw_on_access(compressor)) return this;
            var expression = this.expression.drop_side_effect_free(compressor, first_in_statement);
            if (!expression) return this.property.drop_side_effect_free(compressor, first_in_statement);
            var property = this.property.drop_side_effect_free(compressor);
            if (!property) return expression;
            return make_sequence(this, [expression, property]);
        });
        def(AST_Sequence, function (compressor) {
            var last = this.expressions[this.expressions.length - 1];
            var expr = last.drop_side_effect_free(compressor);
            if (expr === last) return this;
            var expressions = this.expressions.slice(0, -1);
            if (expr) merge_sequence(expressions, expr);
            return make_sequence(this, expressions);
        });
    })(function (node, func) {
        node.DEFMETHOD("drop_side_effect_free", func);
    });

    OPT(AST_SimpleStatement, function (self, compressor) {
        if (compressor.option("side_effects")) {
            var body = self.body;
            var node = body.drop_side_effect_free(compressor, true);
            if (!node) {
                compressor.warn("Dropping side-effect-free statement [{file}:{line},{col}]", self.start);
                return make_node(AST_EmptyStatement, self);
            }
            if (node !== body) {
                return make_node(AST_SimpleStatement, self, {body: node});
            }
        }
        return self;
    });

    OPT(AST_DWLoop, function (self, compressor) {
        if (!compressor.option("loops")) return self;
        var cond = self.condition.evaluate(compressor);
        if (cond !== self.condition) {
            if (cond) {
                return make_node(AST_For, self, {
                    body: self.body
                });
            }
            if (compressor.option("dead_code") && self instanceof AST_While) {
                var a = [];
                extract_declarations_from_unreachable_code(compressor, self.body, a);
                return make_node(AST_BlockStatement, self, {body: a}).optimize(compressor);
            }
            if (self instanceof AST_Do) {
                var has_loop_control = false;
                var tw = new TreeWalker(function (node) {
                    if (node instanceof AST_Scope || has_loop_control) return true;
                    if (node instanceof AST_LoopControl && tw.loopcontrol_target(node) === self)
                        return has_loop_control = true;
                });
                var parent = compressor.parent();
                (parent instanceof AST_LabeledStatement ? parent : self).walk(tw);
                if (!has_loop_control) return self.body;
            }
        }
        if (self instanceof AST_While) {
            return make_node(AST_For, self, self).optimize(compressor);
        }
        return self;
    });

    function if_break_in_loop(self, compressor) {
        function drop_it(rest) {
            rest = as_statement_array(rest);
            if (self.body instanceof AST_BlockStatement) {
                self.body = self.body.clone();
                self.body.body = rest.concat(self.body.body.slice(1));
                self.body = self.body.transform(compressor);
            } else {
                self.body = make_node(AST_BlockStatement, self.body, {
                    body: rest
                }).transform(compressor);
            }
            if_break_in_loop(self, compressor);
        }

        var first = self.body instanceof AST_BlockStatement ? self.body.body[0] : self.body;
        if (first instanceof AST_If) {
            if (first.body instanceof AST_Break
                && compressor.loopcontrol_target(first.body) === compressor.self()) {
                if (self.condition) {
                    self.condition = make_node(AST_Binary, self.condition, {
                        left: self.condition,
                        operator: "&&",
                        right: first.condition.negate(compressor),
                    });
                } else {
                    self.condition = first.condition.negate(compressor);
                }
                drop_it(first.alternative);
            }
            else if (first.alternative instanceof AST_Break
                && compressor.loopcontrol_target(first.alternative) === compressor.self()) {
                if (self.condition) {
                    self.condition = make_node(AST_Binary, self.condition, {
                        left: self.condition,
                        operator: "&&",
                        right: first.condition,
                    });
                } else {
                    self.condition = first.condition;
                }
                drop_it(first.body);
            }
        }
    };

    OPT(AST_For, function (self, compressor) {
        if (!compressor.option("loops")) return self;
        if (self.condition) {
            var cond = self.condition.evaluate(compressor);
            if (compressor.option("dead_code") && !cond) {
                var a = [];
                if (self.init instanceof AST_Statement) {
                    a.push(self.init);
                }
                else if (self.init) {
                    a.push(make_node(AST_SimpleStatement, self.init, {
                        body: self.init
                    }));
                }
                extract_declarations_from_unreachable_code(compressor, self.body, a);
                return make_node(AST_BlockStatement, self, {body: a}).optimize(compressor);
            }
            if (cond !== self.condition) {
                cond = make_node_from_constant(cond, self.condition).transform(compressor);
                self.condition = best_of_expression(cond, self.condition);
            }
        }
        if_break_in_loop(self, compressor);
        return self;
    });

    OPT(AST_If, function (self, compressor) {
        if (is_empty(self.alternative)) self.alternative = null;

        if (!compressor.option("conditionals")) return self;
        // if condition can be statically determined, warn and drop
        // one of the blocks.  note, statically determined implies
        // “has no side effects”; also it doesn't work for cases like
        // `x && true`, though it probably should.
        var cond = self.condition.evaluate(compressor);
        if (cond !== self.condition) {
            if (cond) {
                compressor.warn("Condition always true [{file}:{line},{col}]", self.condition.start);
                if (compressor.option("dead_code")) {
                    var a = [];
                    if (self.alternative) {
                        extract_declarations_from_unreachable_code(compressor, self.alternative, a);
                    }
                    a.push(self.body);
                    return make_node(AST_BlockStatement, self, {body: a}).optimize(compressor);
                }
            } else {
                compressor.warn("Condition always false [{file}:{line},{col}]", self.condition.start);
                if (compressor.option("dead_code")) {
                    var a = [];
                    extract_declarations_from_unreachable_code(compressor, self.body, a);
                    if (self.alternative) a.push(self.alternative);
                    return make_node(AST_BlockStatement, self, {body: a}).optimize(compressor);
                }
            }
            cond = make_node_from_constant(cond, self.condition).transform(compressor);
            self.condition = best_of_expression(cond, self.condition);
        }
        var negated = self.condition.negate(compressor);
        var self_condition_length = self.condition.print_to_string().length;
        var negated_length = negated.print_to_string().length;
        var negated_is_best = negated_length < self_condition_length;
        if (self.alternative && negated_is_best) {
            negated_is_best = false; // because we already do the switch here.
            // no need to swap values of self_condition_length and negated_length
            // here because they are only used in an equality comparison later on.
            self.condition = negated;
            var tmp = self.body;
            self.body = self.alternative || make_node(AST_EmptyStatement, self);
            self.alternative = tmp;
        }
        if (is_empty(self.body) && is_empty(self.alternative)) {
            return make_node(AST_SimpleStatement, self.condition, {
                body: self.condition.clone()
            }).optimize(compressor);
        }
        if (self.body instanceof AST_SimpleStatement
            && self.alternative instanceof AST_SimpleStatement) {
            return make_node(AST_SimpleStatement, self, {
                body: make_node(AST_Conditional, self, {
                    condition: self.condition,
                    consequent: self.body.body,
                    alternative: self.alternative.body
                })
            }).optimize(compressor);
        }
        if (is_empty(self.alternative) && self.body instanceof AST_SimpleStatement) {
            if (self_condition_length === negated_length && !negated_is_best
                && self.condition instanceof AST_Binary && self.condition.operator == "||") {
                // although the code length of self.condition and negated are the same,
                // negated does not require additional surrounding parentheses.
                // see https://github.com/mishoo/UglifyJS2/issues/979
                negated_is_best = true;
            }
            if (negated_is_best) return make_node(AST_SimpleStatement, self, {
                body: make_node(AST_Binary, self, {
                    operator: "||",
                    left: negated,
                    right: self.body.body
                })
            }).optimize(compressor);
            return make_node(AST_SimpleStatement, self, {
                body: make_node(AST_Binary, self, {
                    operator: "&&",
                    left: self.condition,
                    right: self.body.body
                })
            }).optimize(compressor);
        }
        if (self.body instanceof AST_EmptyStatement
            && self.alternative instanceof AST_SimpleStatement) {
            return make_node(AST_SimpleStatement, self, {
                body: make_node(AST_Binary, self, {
                    operator: "||",
                    left: self.condition,
                    right: self.alternative.body
                })
            }).optimize(compressor);
        }
        if (self.body instanceof AST_Exit
            && self.alternative instanceof AST_Exit
            && self.body.TYPE == self.alternative.TYPE) {
            return make_node(self.body.CTOR, self, {
                value: make_node(AST_Conditional, self, {
                    condition: self.condition,
                    consequent: self.body.value || make_node(AST_Undefined, self.body),
                    alternative: self.alternative.value || make_node(AST_Undefined, self.alternative)
                }).transform(compressor)
            }).optimize(compressor);
        }
        if (self.body instanceof AST_If
            && !self.body.alternative
            && !self.alternative) {
            self = make_node(AST_If, self, {
                condition: make_node(AST_Binary, self.condition, {
                    operator: "&&",
                    left: self.condition,
                    right: self.body.condition
                }),
                body: self.body.body,
                alternative: null
            });
        }
        if (aborts(self.body)) {
            if (self.alternative) {
                var alt = self.alternative;
                self.alternative = null;
                return make_node(AST_BlockStatement, self, {
                    body: [self, alt]
                }).optimize(compressor);
            }
        }
        if (aborts(self.alternative)) {
            var body = self.body;
            self.body = self.alternative;
            self.condition = negated_is_best ? negated : self.condition.negate(compressor);
            self.alternative = null;
            return make_node(AST_BlockStatement, self, {
                body: [self, body]
            }).optimize(compressor);
        }
        return self;
    });

    OPT(AST_Switch, function (self, compressor) {
        if (!compressor.option("switches")) return self;
        var branch;
        var value = self.expression.evaluate(compressor);
        if (value !== self.expression) {
            var expression = make_node_from_constant(value, self.expression).transform(compressor);
            self.expression = best_of_expression(expression, self.expression);
        }
        if (!compressor.option("dead_code")) return self;
        var decl = [];
        var body = [];
        var default_branch;
        var exact_match;
        for (var i = 0, len = self.body.length; i < len && !exact_match; i++) {
            branch = self.body[i];
            if (branch instanceof AST_Default) {
                if (!default_branch) {
                    default_branch = branch;
                } else {
                    eliminate_branch(branch, body[body.length - 1]);
                }
            } else if (value !== self.expression) {
                var exp = branch.expression.evaluate(compressor);
                if (exp === value) {
                    exact_match = branch;
                    if (default_branch) {
                        var default_index = body.indexOf(default_branch);
                        body.splice(default_index, 1);
                        eliminate_branch(default_branch, body[default_index - 1]);
                        default_branch = null;
                    }
                } else if (exp !== branch.expression) {
                    eliminate_branch(branch, body[body.length - 1]);
                    continue;
                }
            }
            if (aborts(branch)) {
                var prev = body[body.length - 1];
                if (aborts(prev) && prev.body.length == branch.body.length
                    && make_node(AST_BlockStatement, prev, prev).equivalent_to(make_node(AST_BlockStatement, branch, branch))) {
                    prev.body = [];
                }
            }
            body.push(branch);
        }
        while (i < len) eliminate_branch(self.body[i++], body[body.length - 1]);
        if (body.length > 0) {
            body[0].body = decl.concat(body[0].body);
        }
        self.body = body;
        while (branch = body[body.length - 1]) {
            var stat = branch.body[branch.body.length - 1];
            if (stat instanceof AST_Break && compressor.loopcontrol_target(stat) === self)
                branch.body.pop();
            if (branch.body.length || branch instanceof AST_Case
                && (default_branch || branch.expression.has_side_effects(compressor))) break;
            if (body.pop() === default_branch) default_branch = null;
        }
        if (body.length == 0) {
            return make_node(AST_BlockStatement, self, {
                body: decl.concat(make_node(AST_SimpleStatement, self.expression, {
                    body: self.expression
                }))
            }).optimize(compressor);
        }
        if (body.length == 1 && (body[0] === exact_match || body[0] === default_branch)) {
            var has_break = false;
            var tw = new TreeWalker(function (node) {
                if (has_break
                    || node instanceof AST_Lambda
                    || node instanceof AST_SimpleStatement) return true;
                if (node instanceof AST_Break && tw.loopcontrol_target(node) === self)
                    has_break = true;
            });
            self.walk(tw);
            if (!has_break) {
                body = body[0].body.slice();
                body.unshift(make_node(AST_SimpleStatement, self.expression, {
                    body: self.expression
                }));
                return make_node(AST_BlockStatement, self, {
                    body: body
                }).optimize(compressor);
            }
        }
        return self;

        function eliminate_branch(branch, prev) {
            if (prev && !aborts(prev)) {
                prev.body = prev.body.concat(branch.body);
            } else {
                extract_declarations_from_unreachable_code(compressor, branch, decl);
            }
        }
    });

    OPT(AST_Try, function (self, compressor) {
        tighten_body(self.body, compressor);
        if (self.bcatch && self.bfinally && all(self.bfinally.body, is_empty)) self.bfinally = null;
        if (all(self.body, is_empty)) {
            var body = [];
            if (self.bcatch) extract_declarations_from_unreachable_code(compressor, self.bcatch, body);
            if (self.bfinally) body = body.concat(self.bfinally.body);
            return make_node(AST_BlockStatement, self, {
                body: body
            }).optimize(compressor);
        }
        return self;
    });

    AST_Definitions.DEFMETHOD("remove_initializers", function () {
        this.definitions.forEach(function (def) {
            def.value = null
        });
    });

    AST_Definitions.DEFMETHOD("to_assignments", function (compressor) {
        var reduce_vars = compressor.option("reduce_vars");
        var assignments = this.definitions.reduce(function (a, def) {
            if (def.value) {
                var name = make_node(AST_SymbolRef, def.name, def.name);
                a.push(make_node(AST_Assign, def, {
                    operator: "=",
                    left: name,
                    right: def.value
                }));
                if (reduce_vars) name.definition().fixed = false;
            }
            return a;
        }, []);
        if (assignments.length == 0) return null;
        return make_sequence(this, assignments);
    });

    OPT(AST_Definitions, function (self, compressor) {
        if (self.definitions.length == 0)
            return make_node(AST_EmptyStatement, self);
        return self;
    });

    OPT(AST_Call, function (self, compressor) {
        var exp = self.expression;
        var fn = exp;
        if (compressor.option("unused")
            && (fn instanceof AST_Function
            || compressor.option("reduce_vars")
            && fn instanceof AST_SymbolRef
            && (fn = fn.fixed_value()) instanceof AST_Function)
            && !fn.uses_arguments
            && !fn.uses_eval) {
            var pos = 0, last = 0;
            for (var i = 0, len = self.args.length; i < len; i++) {
                var trim = i >= fn.argnames.length;
                if (trim || fn.argnames[i].__unused) {
                    var node = self.args[i].drop_side_effect_free(compressor);
                    if (node) {
                        self.args[pos++] = node;
                    } else if (!trim) {
                        self.args[pos++] = make_node(AST_Number, self.args[i], {
                            value: 0
                        });
                        continue;
                    }
                } else {
                    self.args[pos++] = self.args[i];
                }
                last = pos;
            }
            self.args.length = last;
        }
        if (compressor.option("unsafe")) {
            if (is_undeclared_ref(exp)) {
                switch (exp.name) {
                    case "Array":
                        if (self.args.length != 1) {
                            return make_node(AST_Array, self, {
                                elements: self.args
                            }).optimize(compressor);
                        }
                        break;
                    case "Object":
                        if (self.args.length == 0) {
                            return make_node(AST_Object, self, {
                                properties: []
                            });
                        }
                        break;
                    case "String":
                        if (self.args.length == 0) return make_node(AST_String, self, {
                            value: ""
                        });
                        if (self.args.length <= 1) return make_node(AST_Binary, self, {
                            left: self.args[0],
                            operator: "+",
                            right: make_node(AST_String, self, {value: ""})
                        }).optimize(compressor);
                        break;
                    case "Number":
                        if (self.args.length == 0) return make_node(AST_Number, self, {
                            value: 0
                        });
                        if (self.args.length == 1) return make_node(AST_UnaryPrefix, self, {
                            expression: self.args[0],
                            operator: "+"
                        }).optimize(compressor);
                    case "Boolean":
                        if (self.args.length == 0) return make_node(AST_False, self);
                        if (self.args.length == 1) return make_node(AST_UnaryPrefix, self, {
                            expression: make_node(AST_UnaryPrefix, self, {
                                expression: self.args[0],
                                operator: "!"
                            }),
                            operator: "!"
                        }).optimize(compressor);
                        break;
                }
            }
            else if (exp instanceof AST_Dot && exp.property == "toString" && self.args.length == 0) {
                return make_node(AST_Binary, self, {
                    left: make_node(AST_String, self, {value: ""}),
                    operator: "+",
                    right: exp.expression
                }).optimize(compressor);
            }
            else if (exp instanceof AST_Dot && exp.expression instanceof AST_Array && exp.property == "join") EXIT: {
                var separator;
                if (self.args.length > 0) {
                    separator = self.args[0].evaluate(compressor);
                    if (separator === self.args[0]) break EXIT; // not a constant
                }
                var elements = [];
                var consts = [];
                exp.expression.elements.forEach(function (el) {
                    var value = el.evaluate(compressor);
                    if (value !== el) {
                        consts.push(value);
                    } else {
                        if (consts.length > 0) {
                            elements.push(make_node(AST_String, self, {
                                value: consts.join(separator)
                            }));
                            consts.length = 0;
                        }
                        elements.push(el);
                    }
                });
                if (consts.length > 0) {
                    elements.push(make_node(AST_String, self, {
                        value: consts.join(separator)
                    }));
                }
                if (elements.length == 0) return make_node(AST_String, self, {value: ""});
                if (elements.length == 1) {
                    if (elements[0].is_string(compressor)) {
                        return elements[0];
                    }
                    return make_node(AST_Binary, elements[0], {
                        operator: "+",
                        left: make_node(AST_String, self, {value: ""}),
                        right: elements[0]
                    });
                }
                if (separator == "") {
                    var first;
                    if (elements[0].is_string(compressor)
                        || elements[1].is_string(compressor)) {
                        first = elements.shift();
                    } else {
                        first = make_node(AST_String, self, {value: ""});
                    }
                    return elements.reduce(function (prev, el) {
                        return make_node(AST_Binary, el, {
                            operator: "+",
                            left: prev,
                            right: el
                        });
                    }, first).optimize(compressor);
                }
                // need this awkward cloning to not affect original element
                // best_of will decide which one to get through.
                var node = self.clone();
                node.expression = node.expression.clone();
                node.expression.expression = node.expression.expression.clone();
                node.expression.expression.elements = elements;
                return best_of(compressor, self, node);
            }
            else if (exp instanceof AST_Dot && exp.expression.is_string(compressor) && exp.property == "charAt") {
                var arg = self.args[0];
                var index = arg ? arg.evaluate(compressor) : 0;
                if (index !== arg) {
                    return make_node(AST_Sub, exp, {
                        expression: exp.expression,
                        property: make_node_from_constant(index | 0, arg || exp)
                    }).optimize(compressor);
                }
            }
        }
        if (compressor.option("unsafe_Func")
            && is_undeclared_ref(exp)
            && exp.name == "Function") {
            // new Function() => function(){}
            if (self.args.length == 0) return make_node(AST_Function, self, {
                argnames: [],
                body: []
            });
            if (all(self.args, function (x) {
                    return x instanceof AST_String;
                })) {
                // quite a corner-case, but we can handle it:
                //   https://github.com/mishoo/UglifyJS2/issues/203
                // if the code argument is a constant, then we can minify it.
                try {
                    var code = "n(function(" + self.args.slice(0, -1).map(function (arg) {
                            return arg.value;
                        }).join(",") + "){" + self.args[self.args.length - 1].value + "})";
                    var ast = parse(code);
                    var mangle = {ie8: compressor.option("ie8")};
                    ast.figure_out_scope(mangle);
                    var comp = new Compressor(compressor.options);
                    ast = ast.transform(comp);
                    ast.figure_out_scope(mangle);
                    base54.reset();
                    ast.compute_char_frequency(mangle);
                    ast.mangle_names(mangle);
                    var fun;
                    ast.walk(new TreeWalker(function (node) {
                        if (fun) return true;
                        if (node instanceof AST_Lambda) {
                            fun = node;
                            return true;
                        }
                    }));
                    var code = OutputStream();
                    AST_BlockStatement.prototype._codegen.call(fun, fun, code);
                    self.args = [
                        make_node(AST_String, self, {
                            value: fun.argnames.map(function (arg) {
                                return arg.print_to_string();
                            }).join(",")
                        }),
                        make_node(AST_String, self.args[self.args.length - 1], {
                            value: code.get().replace(/^\{|\}$/g, "")
                        })
                    ];
                    return self;
                } catch (ex) {
                    if (ex instanceof JS_Parse_Error) {
                        compressor.warn("Error parsing code passed to new Function [{file}:{line},{col}]", self.args[self.args.length - 1].start);
                        compressor.warn(ex.toString());
                    } else {
                        throw ex;
                    }
                }
            }
        }
        var stat = fn instanceof AST_Function && fn.body[0];
        if (compressor.option("inline") && stat instanceof AST_Return) {
            var value = stat.value;
            if (!value || value.is_constant_expression()) {
                var args = self.args.concat(value || make_node(AST_Undefined, self));
                return make_sequence(self, args).optimize(compressor);
            }
        }
        if (exp instanceof AST_Function) {
            if (compressor.option("inline")
                && !exp.name
                && !exp.uses_arguments
                && !exp.uses_eval
                && exp.body.length == 1
                && all(exp.argnames, function (arg) {
                    return arg.__unused;
                })
                && !self.has_pure_annotation(compressor)) {
                var value;
                if (stat instanceof AST_Return) {
                    value = stat.value;
                } else if (stat instanceof AST_SimpleStatement) {
                    value = make_node(AST_UnaryPrefix, stat, {
                        operator: "void",
                        expression: stat.body
                    });
                }
                if (value) {
                    var tw = new TreeWalker(function (node) {
                        if (!value) return true;
                        if (node instanceof AST_SymbolRef) {
                            var ref = node.scope.find_variable(node);
                            if (ref && ref.scope.parent_scope === fn.parent_scope) {
                                value = null;
                                return true;
                            }
                        }
                        if (node instanceof AST_This && !tw.find_parent(AST_Scope)) {
                            value = null;
                            return true;
                        }
                    });
                    value.walk(tw);
                }
                if (value) {
                    var args = self.args.concat(value);
                    return make_sequence(self, args).optimize(compressor);
                }
            }
            if (compressor.option("side_effects") && all(exp.body, is_empty)) {
                var args = self.args.concat(make_node(AST_Undefined, self));
                return make_sequence(self, args).optimize(compressor);
            }
        }
        if (compressor.option("drop_console")) {
            if (exp instanceof AST_PropAccess) {
                var name = exp.expression;
                while (name.expression) {
                    name = name.expression;
                }
                if (is_undeclared_ref(name) && name.name == "console") {
                    return make_node(AST_Undefined, self).optimize(compressor);
                }
            }
        }
        if (compressor.option("negate_iife")
            && compressor.parent() instanceof AST_SimpleStatement
            && is_iife_call(self)) {
            return self.negate(compressor, true);
        }
        var ev = self.evaluate(compressor);
        if (ev !== self) {
            ev = make_node_from_constant(ev, self).optimize(compressor);
            return best_of(compressor, ev, self);
        }
        return self;
    });

    OPT(AST_New, function (self, compressor) {
        if (compressor.option("unsafe")) {
            var exp = self.expression;
            if (is_undeclared_ref(exp)) {
                switch (exp.name) {
                    case "Object":
                    case "RegExp":
                    case "Function":
                    case "Error":
                    case "Array":
                        return make_node(AST_Call, self, self).transform(compressor);
                }
            }
        }
        return self;
    });

    OPT(AST_Sequence, function (self, compressor) {
        if (!compressor.option("side_effects")) return self;
        var expressions = [];
        filter_for_side_effects();
        var end = expressions.length - 1;
        trim_right_for_undefined();
        if (end > 0 && compressor.option("cascade")) trim_left_for_assignment();
        if (end == 0) {
            self = maintain_this_binding(compressor.parent(), self, expressions[0]);
            if (!(self instanceof AST_Sequence)) self = self.optimize(compressor);
            return self;
        }
        self.expressions = expressions;
        return self;

        function filter_for_side_effects() {
            var first = first_in_statement(compressor);
            var last = self.expressions.length - 1;
            self.expressions.forEach(function (expr, index) {
                if (index < last) expr = expr.drop_side_effect_free(compressor, first);
                if (expr) {
                    merge_sequence(expressions, expr);
                    first = false;
                }
            });
        }

        function trim_right_for_undefined() {
            while (end > 0 && is_undefined(expressions[end], compressor)) end--;
            if (end < expressions.length - 1) {
                expressions[end] = make_node(AST_UnaryPrefix, self, {
                    operator: "void",
                    expression: expressions[end]
                });
                expressions.length = end + 1;
            }
        }

        function trim_left_for_assignment() {
            for (var i = 0, j = 1; j <= end; j++) {
                var left = expressions[i];
                var cdr = expressions[j];
                if (left instanceof AST_Assign
                    && !left.left.has_side_effects(compressor)) {
                    left = left.left;
                } else if (left instanceof AST_Unary
                    && (left.operator == "++" || left.operator == "--")) {
                    left = left.expression;
                } else left = null;
                if (!left || is_lhs_read_only(left)) {
                    expressions[++i] = cdr;
                    continue;
                }
                var parent = null, field;
                expressions[j] = cdr = cdr.clone();
                while (true) {
                    if (cdr.equivalent_to(left)) {
                        var car = expressions[i];
                        if (car instanceof AST_UnaryPostfix) {
                            car = make_node(AST_UnaryPrefix, car, {
                                operator: car.operator,
                                expression: left
                            });
                        } else {
                            car.write_only = false;
                        }
                        if (parent) {
                            parent[field] = car;
                            expressions[i] = expressions[j];
                        } else {
                            expressions[i] = car;
                        }
                        break;
                    }
                    if (cdr instanceof AST_Binary && !(cdr instanceof AST_Assign)) {
                        if (cdr.left.is_constant()) {
                            if (cdr.operator == "||" || cdr.operator == "&&") {
                                expressions[++i] = expressions[j];
                                break;
                            }
                            field = "right";
                        } else {
                            field = "left";
                        }
                    } else if (cdr instanceof AST_Call
                        && !(left instanceof AST_PropAccess && cdr.expression.equivalent_to(left))
                        || cdr instanceof AST_PropAccess
                        || cdr instanceof AST_Unary && !unary_side_effects(cdr.operator)) {
                        field = "expression";
                    } else if (cdr instanceof AST_Conditional) {
                        field = "condition";
                    } else {
                        expressions[++i] = expressions[j];
                        break;
                    }
                    parent = cdr;
                    cdr = cdr[field] = cdr[field].clone();
                }
            }
            end = i;
            expressions.length = end + 1;
        }
    });

    AST_Unary.DEFMETHOD("lift_sequences", function (compressor) {
        if (compressor.option("sequences")) {
            if (this.expression instanceof AST_Sequence) {
                var x = this.expression.expressions.slice();
                var e = this.clone();
                e.expression = x.pop();
                x.push(e);
                return make_sequence(this, x).optimize(compressor);
            }
        }
        return this;
    });

    OPT(AST_UnaryPostfix, function (self, compressor) {
        return self.lift_sequences(compressor);
    });

    OPT(AST_UnaryPrefix, function (self, compressor) {
        var e = self.expression;
        if (self.operator == "delete"
            && !(e instanceof AST_SymbolRef
            || e instanceof AST_PropAccess
            || e instanceof AST_NaN
            || e instanceof AST_Infinity
            || e instanceof AST_Undefined)) {
            if (e instanceof AST_Sequence) {
                e = e.expressions.slice();
                e.push(make_node(AST_True, self));
                return make_sequence(self, e).optimize(compressor);
            }
            return make_sequence(self, [e, make_node(AST_True, self)]).optimize(compressor);
        }
        var seq = self.lift_sequences(compressor);
        if (seq !== self) {
            return seq;
        }
        if (compressor.option("side_effects") && self.operator == "void") {
            e = e.drop_side_effect_free(compressor);
            if (e) {
                self.expression = e;
                return self;
            } else {
                return make_node(AST_Undefined, self).optimize(compressor);
            }
        }
        if (compressor.option("booleans") && compressor.in_boolean_context()) {
            switch (self.operator) {
                case "!":
                    if (e instanceof AST_UnaryPrefix && e.operator == "!") {
                        // !!foo ==> foo, if we're in boolean context
                        return e.expression;
                    }
                    if (e instanceof AST_Binary) {
                        self = best_of(compressor, self, e.negate(compressor, first_in_statement(compressor)));
                    }
                    break;
                case "typeof":
                    // typeof always returns a non-empty string, thus it's
                    // always true in booleans
                    compressor.warn("Boolean expression always true [{file}:{line},{col}]", self.start);
                    return (e instanceof AST_SymbolRef ? make_node(AST_True, self) : make_sequence(self, [
                        e,
                        make_node(AST_True, self)
                    ])).optimize(compressor);
            }
        }
        if (self.operator == "-" && e instanceof AST_Infinity) {
            e = e.transform(compressor);
        }
        if (e instanceof AST_Binary
            && (self.operator == "+" || self.operator == "-")
            && (e.operator == "*" || e.operator == "/" || e.operator == "%")) {
            return make_node(AST_Binary, self, {
                operator: e.operator,
                left: make_node(AST_UnaryPrefix, e.left, {
                    operator: self.operator,
                    expression: e.left
                }),
                right: e.right
            });
        }
        // avoids infinite recursion of numerals
        if (self.operator != "-"
            || !(e instanceof AST_Number || e instanceof AST_Infinity)) {
            var ev = self.evaluate(compressor);
            if (ev !== self) {
                ev = make_node_from_constant(ev, self).optimize(compressor);
                return best_of(compressor, ev, self);
            }
        }
        return self;
    });

    AST_Binary.DEFMETHOD("lift_sequences", function (compressor) {
        if (compressor.option("sequences")) {
            if (this.left instanceof AST_Sequence) {
                var x = this.left.expressions.slice();
                var e = this.clone();
                e.left = x.pop();
                x.push(e);
                return make_sequence(this, x).optimize(compressor);
            }
            if (this.right instanceof AST_Sequence && !this.left.has_side_effects(compressor)) {
                var assign = this.operator == "=" && this.left instanceof AST_SymbolRef;
                var x = this.right.expressions;
                var last = x.length - 1;
                for (var i = 0; i < last; i++) {
                    if (!assign && x[i].has_side_effects(compressor)) break;
                }
                if (i == last) {
                    x = x.slice();
                    var e = this.clone();
                    e.right = x.pop();
                    x.push(e);
                    return make_sequence(this, x).optimize(compressor);
                } else if (i > 0) {
                    var e = this.clone();
                    e.right = make_sequence(this.right, x.slice(i));
                    x = x.slice(0, i);
                    x.push(e);
                    return make_sequence(this, x).optimize(compressor);
                }
            }
        }
        return this;
    });

    var commutativeOperators = makePredicate("== === != !== * & | ^");

    OPT(AST_Binary, function (self, compressor) {
        function reversible() {
            return self.left.is_constant()
                || self.right.is_constant()
                || !self.left.has_side_effects(compressor)
                && !self.right.has_side_effects(compressor);
        }

        function reverse(op) {
            if (reversible()) {
                if (op) self.operator = op;
                var tmp = self.left;
                self.left = self.right;
                self.right = tmp;
            }
        }

        if (commutativeOperators(self.operator)) {
            if (self.right.is_constant()
                && !self.left.is_constant()) {
                // if right is a constant, whatever side effects the
                // left side might have could not influence the
                // result.  hence, force switch.

                if (!(self.left instanceof AST_Binary
                    && PRECEDENCE[self.left.operator] >= PRECEDENCE[self.operator])) {
                    reverse();
                }
            }
        }
        self = self.lift_sequences(compressor);
        if (compressor.option("comparisons")) switch (self.operator) {
            case "===":
            case "!==":
                if ((self.left.is_string(compressor) && self.right.is_string(compressor)) ||
                    (self.left.is_number(compressor) && self.right.is_number(compressor)) ||
                    (self.left.is_boolean() && self.right.is_boolean())) {
                    self.operator = self.operator.substr(0, 2);
                }
            // XXX: intentionally falling down to the next case
            case "==":
            case "!=":
                // "undefined" == typeof x => undefined === x
                if (compressor.option("typeofs")
                    && self.left instanceof AST_String
                    && self.left.value == "undefined"
                    && self.right instanceof AST_UnaryPrefix
                    && self.right.operator == "typeof") {
                    var expr = self.right.expression;
                    if (expr instanceof AST_SymbolRef ? expr.is_declared(compressor)
                            : !(expr instanceof AST_PropAccess && compressor.option("ie8"))) {
                        self.right = expr;
                        self.left = make_node(AST_Undefined, self.left).optimize(compressor);
                        if (self.operator.length == 2) self.operator += "=";
                    }
                }
                break;
        }
        if (compressor.option("booleans") && self.operator == "+" && compressor.in_boolean_context()) {
            var ll = self.left.evaluate(compressor);
            var rr = self.right.evaluate(compressor);
            if (ll && typeof ll == "string") {
                compressor.warn("+ in boolean context always true [{file}:{line},{col}]", self.start);
                return make_sequence(self, [
                    self.right,
                    make_node(AST_True, self)
                ]).optimize(compressor);
            }
            if (rr && typeof rr == "string") {
                compressor.warn("+ in boolean context always true [{file}:{line},{col}]", self.start);
                return make_sequence(self, [
                    self.left,
                    make_node(AST_True, self)
                ]).optimize(compressor);
            }
        }
        if (compressor.option("comparisons") && self.is_boolean()) {
            if (!(compressor.parent() instanceof AST_Binary)
                || compressor.parent() instanceof AST_Assign) {
                var negated = make_node(AST_UnaryPrefix, self, {
                    operator: "!",
                    expression: self.negate(compressor, first_in_statement(compressor))
                });
                self = best_of(compressor, self, negated);
            }
            if (compressor.option("unsafe_comps")) {
                switch (self.operator) {
                    case "<":
                        reverse(">");
                        break;
                    case "<=":
                        reverse(">=");
                        break;
                }
            }
        }
        if (self.operator == "+") {
            if (self.right instanceof AST_String
                && self.right.getValue() == ""
                && self.left.is_string(compressor)) {
                return self.left;
            }
            if (self.left instanceof AST_String
                && self.left.getValue() == ""
                && self.right.is_string(compressor)) {
                return self.right;
            }
            if (self.left instanceof AST_Binary
                && self.left.operator == "+"
                && self.left.left instanceof AST_String
                && self.left.left.getValue() == ""
                && self.right.is_string(compressor)) {
                self.left = self.left.right;
                return self.transform(compressor);
            }
        }
        if (compressor.option("evaluate")) {
            switch (self.operator) {
                case "&&":
                    var ll = self.left.evaluate(compressor);
                    if (!ll) {
                        compressor.warn("Condition left of && always false [{file}:{line},{col}]", self.start);
                        return maintain_this_binding(compressor.parent(), self, self.left).optimize(compressor);
                    } else if (ll !== self.left) {
                        compressor.warn("Condition left of && always true [{file}:{line},{col}]", self.start);
                        return maintain_this_binding(compressor.parent(), self, self.right).optimize(compressor);
                    }
                    if (compressor.option("booleans") && compressor.in_boolean_context()) {
                        var rr = self.right.evaluate(compressor);
                        if (!rr) {
                            compressor.warn("Boolean && always false [{file}:{line},{col}]", self.start);
                            return make_sequence(self, [
                                self.left,
                                make_node(AST_False, self)
                            ]).optimize(compressor);
                        } else if (rr !== self.right) {
                            compressor.warn("Dropping side-effect-free && in boolean context [{file}:{line},{col}]", self.start);
                            return self.left.optimize(compressor);
                        }
                    }
                    break;
                case "||":
                    var ll = self.left.evaluate(compressor);
                    if (!ll) {
                        compressor.warn("Condition left of || always false [{file}:{line},{col}]", self.start);
                        return maintain_this_binding(compressor.parent(), self, self.right).optimize(compressor);
                    } else if (ll !== self.left) {
                        compressor.warn("Condition left of || always true [{file}:{line},{col}]", self.start);
                        return maintain_this_binding(compressor.parent(), self, self.left).optimize(compressor);
                    }
                    if (compressor.option("booleans") && compressor.in_boolean_context()) {
                        var rr = self.right.evaluate(compressor);
                        if (!rr) {
                            compressor.warn("Dropping side-effect-free || in boolean context [{file}:{line},{col}]", self.start);
                            return self.left.optimize(compressor);
                        } else if (rr !== self.right) {
                            compressor.warn("Boolean || always true [{file}:{line},{col}]", self.start);
                            return make_sequence(self, [
                                self.left,
                                make_node(AST_True, self)
                            ]).optimize(compressor);
                        }
                    }
                    break;
            }
            var associative = true;
            switch (self.operator) {
                case "+":
                    // "foo" + ("bar" + x) => "foobar" + x
                    if (self.left instanceof AST_Constant
                        && self.right instanceof AST_Binary
                        && self.right.operator == "+"
                        && self.right.left instanceof AST_Constant
                        && self.right.is_string(compressor)) {
                        self = make_node(AST_Binary, self, {
                            operator: "+",
                            left: make_node(AST_String, self.left, {
                                value: "" + self.left.getValue() + self.right.left.getValue(),
                                start: self.left.start,
                                end: self.right.left.end
                            }),
                            right: self.right.right
                        });
                    }
                    // (x + "foo") + "bar" => x + "foobar"
                    if (self.right instanceof AST_Constant
                        && self.left instanceof AST_Binary
                        && self.left.operator == "+"
                        && self.left.right instanceof AST_Constant
                        && self.left.is_string(compressor)) {
                        self = make_node(AST_Binary, self, {
                            operator: "+",
                            left: self.left.left,
                            right: make_node(AST_String, self.right, {
                                value: "" + self.left.right.getValue() + self.right.getValue(),
                                start: self.left.right.start,
                                end: self.right.end
                            })
                        });
                    }
                    // (x + "foo") + ("bar" + y) => (x + "foobar") + y
                    if (self.left instanceof AST_Binary
                        && self.left.operator == "+"
                        && self.left.is_string(compressor)
                        && self.left.right instanceof AST_Constant
                        && self.right instanceof AST_Binary
                        && self.right.operator == "+"
                        && self.right.left instanceof AST_Constant
                        && self.right.is_string(compressor)) {
                        self = make_node(AST_Binary, self, {
                            operator: "+",
                            left: make_node(AST_Binary, self.left, {
                                operator: "+",
                                left: self.left.left,
                                right: make_node(AST_String, self.left.right, {
                                    value: "" + self.left.right.getValue() + self.right.left.getValue(),
                                    start: self.left.right.start,
                                    end: self.right.left.end
                                })
                            }),
                            right: self.right.right
                        });
                    }
                    // a + -b => a - b
                    if (self.right instanceof AST_UnaryPrefix
                        && self.right.operator == "-"
                        && self.left.is_number(compressor)) {
                        self = make_node(AST_Binary, self, {
                            operator: "-",
                            left: self.left,
                            right: self.right.expression
                        });
                        break;
                    }
                    // -a + b => b - a
                    if (self.left instanceof AST_UnaryPrefix
                        && self.left.operator == "-"
                        && reversible()
                        && self.right.is_number(compressor)) {
                        self = make_node(AST_Binary, self, {
                            operator: "-",
                            left: self.right,
                            right: self.left.expression
                        });
                        break;
                    }
                case "*":
                    associative = compressor.option("unsafe_math");
                case "&":
                case "|":
                case "^":
                    // a + +b => +b + a
                    if (self.left.is_number(compressor)
                        && self.right.is_number(compressor)
                        && reversible()
                        && !(self.left instanceof AST_Binary
                        && self.left.operator != self.operator
                        && PRECEDENCE[self.left.operator] >= PRECEDENCE[self.operator])) {
                        var reversed = make_node(AST_Binary, self, {
                            operator: self.operator,
                            left: self.right,
                            right: self.left
                        });
                        if (self.right instanceof AST_Constant
                            && !(self.left instanceof AST_Constant)) {
                            self = best_of(compressor, reversed, self);
                        } else {
                            self = best_of(compressor, self, reversed);
                        }
                    }
                    if (associative && self.is_number(compressor)) {
                        // a + (b + c) => (a + b) + c
                        if (self.right instanceof AST_Binary
                            && self.right.operator == self.operator) {
                            self = make_node(AST_Binary, self, {
                                operator: self.operator,
                                left: make_node(AST_Binary, self.left, {
                                    operator: self.operator,
                                    left: self.left,
                                    right: self.right.left,
                                    start: self.left.start,
                                    end: self.right.left.end
                                }),
                                right: self.right.right
                            });
                        }
                        // (n + 2) + 3 => 5 + n
                        // (2 * n) * 3 => 6 + n
                        if (self.right instanceof AST_Constant
                            && self.left instanceof AST_Binary
                            && self.left.operator == self.operator) {
                            if (self.left.left instanceof AST_Constant) {
                                self = make_node(AST_Binary, self, {
                                    operator: self.operator,
                                    left: make_node(AST_Binary, self.left, {
                                        operator: self.operator,
                                        left: self.left.left,
                                        right: self.right,
                                        start: self.left.left.start,
                                        end: self.right.end
                                    }),
                                    right: self.left.right
                                });
                            } else if (self.left.right instanceof AST_Constant) {
                                self = make_node(AST_Binary, self, {
                                    operator: self.operator,
                                    left: make_node(AST_Binary, self.left, {
                                        operator: self.operator,
                                        left: self.left.right,
                                        right: self.right,
                                        start: self.left.right.start,
                                        end: self.right.end
                                    }),
                                    right: self.left.left
                                });
                            }
                        }
                        // (a | 1) | (2 | d) => (3 | a) | b
                        if (self.left instanceof AST_Binary
                            && self.left.operator == self.operator
                            && self.left.right instanceof AST_Constant
                            && self.right instanceof AST_Binary
                            && self.right.operator == self.operator
                            && self.right.left instanceof AST_Constant) {
                            self = make_node(AST_Binary, self, {
                                operator: self.operator,
                                left: make_node(AST_Binary, self.left, {
                                    operator: self.operator,
                                    left: make_node(AST_Binary, self.left.left, {
                                        operator: self.operator,
                                        left: self.left.right,
                                        right: self.right.left,
                                        start: self.left.right.start,
                                        end: self.right.left.end
                                    }),
                                    right: self.left.left
                                }),
                                right: self.right.right
                            });
                        }
                    }
            }
        }
        // x && (y && z)  ==>  x && y && z
        // x || (y || z)  ==>  x || y || z
        // x + ("y" + z)  ==>  x + "y" + z
        // "x" + (y + "z")==>  "x" + y + "z"
        if (self.right instanceof AST_Binary
            && self.right.operator == self.operator
            && (self.operator == "&&"
            || self.operator == "||"
            || (self.operator == "+"
            && (self.right.left.is_string(compressor)
            || (self.left.is_string(compressor)
            && self.right.right.is_string(compressor)))))) {
            self.left = make_node(AST_Binary, self.left, {
                operator: self.operator,
                left: self.left,
                right: self.right.left
            });
            self.right = self.right.right;
            return self.transform(compressor);
        }
        var ev = self.evaluate(compressor);
        if (ev !== self) {
            ev = make_node_from_constant(ev, self).optimize(compressor);
            return best_of(compressor, ev, self);
        }
        return self;
    });

    OPT(AST_SymbolRef, function (self, compressor) {
        var def = self.resolve_defines(compressor);
        if (def) {
            return def.optimize(compressor);
        }
        // testing against !self.scope.uses_with first is an optimization
        if (!compressor.option("ie8")
            && is_undeclared_ref(self)
            && (!self.scope.uses_with || !compressor.find_parent(AST_With))) {
            switch (self.name) {
                case "undefined":
                    return make_node(AST_Undefined, self).optimize(compressor);
                case "NaN":
                    return make_node(AST_NaN, self).optimize(compressor);
                case "Infinity":
                    return make_node(AST_Infinity, self).optimize(compressor);
            }
        }
        if (compressor.option("reduce_vars")
            && is_lhs(self, compressor.parent()) !== self) {
            var d = self.definition();
            var fixed = self.fixed_value();
            if (fixed instanceof AST_Defun) {
                d.fixed = fixed = make_node(AST_Function, fixed, fixed);
            }
            if (compressor.option("unused")
                && fixed instanceof AST_Function
                && d.references.length == 1
                && !(d.scope.uses_arguments && d.orig[0] instanceof AST_SymbolFunarg)
                && !d.scope.uses_eval
                && compressor.find_parent(AST_Scope) === fixed.parent_scope) {
                return fixed.clone(true);
            }
            if (compressor.option("evaluate") && fixed) {
                if (d.should_replace === undefined) {
                    var init = fixed.evaluate(compressor);
                    if (init !== fixed && (compressor.option("unsafe_regexp") || !(init instanceof RegExp))) {
                        init = make_node_from_constant(init, fixed);
                        var value_length = init.optimize(compressor).print_to_string().length;
                        var fn;
                        if (has_symbol_ref(fixed)) {
                            fn = function () {
                                var result = init.optimize(compressor);
                                return result === init ? result.clone(true) : result;
                            };
                        } else {
                            value_length = Math.min(value_length, fixed.print_to_string().length);
                            fn = function () {
                                var result = best_of_expression(init.optimize(compressor), fixed);
                                return result === init || result === fixed ? result.clone(true) : result;
                            };
                        }
                        var name_length = d.name.length;
                        var overhead = 0;
                        if (compressor.option("unused") && !compressor.exposed(d)) {
                            overhead = (name_length + 2 + value_length) / d.references.length;
                        }
                        d.should_replace = value_length <= name_length + overhead ? fn : false;
                    } else {
                        d.should_replace = false;
                    }
                }
                if (d.should_replace) {
                    return d.should_replace();
                }
            }
        }
        return self;

        function has_symbol_ref(value) {
            var found;
            value.walk(new TreeWalker(function (node) {
                if (node instanceof AST_SymbolRef) found = true;
                if (found) return true;
            }));
            return found;
        }
    });

    function is_atomic(lhs, self) {
        return lhs instanceof AST_SymbolRef || lhs.TYPE === self.TYPE;
    }

    OPT(AST_Undefined, function (self, compressor) {
        if (compressor.option("unsafe")) {
            var undef = find_variable(compressor, "undefined");
            if (undef) {
                var ref = make_node(AST_SymbolRef, self, {
                    name: "undefined",
                    scope: undef.scope,
                    thedef: undef
                });
                ref.is_undefined = true;
                return ref;
            }
        }
        var lhs = is_lhs(compressor.self(), compressor.parent());
        if (lhs && is_atomic(lhs, self)) return self;
        return make_node(AST_UnaryPrefix, self, {
            operator: "void",
            expression: make_node(AST_Number, self, {
                value: 0
            })
        });
    });

    OPT(AST_Infinity, function (self, compressor) {
        var lhs = is_lhs(compressor.self(), compressor.parent());
        if (lhs && is_atomic(lhs, self)) return self;
        if (compressor.option("keep_infinity")
            && !(lhs && !is_atomic(lhs, self))
            && !find_variable(compressor, "Infinity"))
            return self;
        return make_node(AST_Binary, self, {
            operator: "/",
            left: make_node(AST_Number, self, {
                value: 1
            }),
            right: make_node(AST_Number, self, {
                value: 0
            })
        });
    });

    OPT(AST_NaN, function (self, compressor) {
        var lhs = is_lhs(compressor.self(), compressor.parent());
        if (lhs && !is_atomic(lhs, self)
            || find_variable(compressor, "NaN")) {
            return make_node(AST_Binary, self, {
                operator: "/",
                left: make_node(AST_Number, self, {
                    value: 0
                }),
                right: make_node(AST_Number, self, {
                    value: 0
                })
            });
        }
        return self;
    });

    var ASSIGN_OPS = ['+', '-', '/', '*', '%', '>>', '<<', '>>>', '|', '^', '&'];
    var ASSIGN_OPS_COMMUTATIVE = ['*', '|', '^', '&'];
    OPT(AST_Assign, function (self, compressor) {
        self = self.lift_sequences(compressor);
        if (self.operator == "=" && self.left instanceof AST_SymbolRef && self.right instanceof AST_Binary) {
            // x = expr1 OP expr2
            if (self.right.left instanceof AST_SymbolRef
                && self.right.left.name == self.left.name
                && member(self.right.operator, ASSIGN_OPS)) {
                // x = x - 2  --->  x -= 2
                self.operator = self.right.operator + "=";
                self.right = self.right.right;
            }
            else if (self.right.right instanceof AST_SymbolRef
                && self.right.right.name == self.left.name
                && member(self.right.operator, ASSIGN_OPS_COMMUTATIVE)
                && !self.right.left.has_side_effects(compressor)) {
                // x = 2 & x  --->  x &= 2
                self.operator = self.right.operator + "=";
                self.right = self.right.left;
            }
        }
        return self;
    });

    OPT(AST_Conditional, function (self, compressor) {
        if (!compressor.option("conditionals")) return self;
        // This looks like lift_sequences(), should probably be under "sequences"
        if (self.condition instanceof AST_Sequence) {
            var expressions = self.condition.expressions.slice();
            self.condition = expressions.pop();
            expressions.push(self);
            return make_sequence(self, expressions);
        }
        var cond = self.condition.evaluate(compressor);
        if (cond !== self.condition) {
            if (cond) {
                compressor.warn("Condition always true [{file}:{line},{col}]", self.start);
                return maintain_this_binding(compressor.parent(), self, self.consequent);
            } else {
                compressor.warn("Condition always false [{file}:{line},{col}]", self.start);
                return maintain_this_binding(compressor.parent(), self, self.alternative);
            }
        }
        var negated = cond.negate(compressor, first_in_statement(compressor));
        if (best_of(compressor, cond, negated) === negated) {
            self = make_node(AST_Conditional, self, {
                condition: negated,
                consequent: self.alternative,
                alternative: self.consequent
            });
        }
        var condition = self.condition;
        var consequent = self.consequent;
        var alternative = self.alternative;
        // x?x:y --> x||y
        if (condition instanceof AST_SymbolRef
            && consequent instanceof AST_SymbolRef
            && condition.definition() === consequent.definition()) {
            return make_node(AST_Binary, self, {
                operator: "||",
                left: condition,
                right: alternative
            });
        }
        // if (foo) exp = something; else exp = something_else;
        //                   |
        //                   v
        // exp = foo ? something : something_else;
        if (consequent instanceof AST_Assign
            && alternative instanceof AST_Assign
            && consequent.operator == alternative.operator
            && consequent.left.equivalent_to(alternative.left)
            && (!self.condition.has_side_effects(compressor)
            || consequent.operator == "="
            && !consequent.left.has_side_effects(compressor))) {
            return make_node(AST_Assign, self, {
                operator: consequent.operator,
                left: consequent.left,
                right: make_node(AST_Conditional, self, {
                    condition: self.condition,
                    consequent: consequent.right,
                    alternative: alternative.right
                })
            });
        }
        // x ? y(a) : y(b) --> y(x ? a : b)
        if (consequent instanceof AST_Call
            && alternative.TYPE === consequent.TYPE
            && consequent.args.length == 1
            && alternative.args.length == 1
            && consequent.expression.equivalent_to(alternative.expression)
            && !consequent.expression.has_side_effects(compressor)) {
            consequent.args[0] = make_node(AST_Conditional, self, {
                condition: self.condition,
                consequent: consequent.args[0],
                alternative: alternative.args[0]
            });
            return consequent;
        }
        // x?y?z:a:a --> x&&y?z:a
        if (consequent instanceof AST_Conditional
            && consequent.alternative.equivalent_to(alternative)) {
            return make_node(AST_Conditional, self, {
                condition: make_node(AST_Binary, self, {
                    left: self.condition,
                    operator: "&&",
                    right: consequent.condition
                }),
                consequent: consequent.consequent,
                alternative: alternative
            });
        }
        // x ? y : y --> x, y
        if (consequent.equivalent_to(alternative)) {
            return make_sequence(self, [
                self.condition,
                consequent
            ]).optimize(compressor);
        }

        if (is_true(self.consequent)) {
            if (is_false(self.alternative)) {
                // c ? true : false ---> !!c
                return booleanize(self.condition);
            }
            // c ? true : x ---> !!c || x
            return make_node(AST_Binary, self, {
                operator: "||",
                left: booleanize(self.condition),
                right: self.alternative
            });
        }
        if (is_false(self.consequent)) {
            if (is_true(self.alternative)) {
                // c ? false : true ---> !c
                return booleanize(self.condition.negate(compressor));
            }
            // c ? false : x ---> !c && x
            return make_node(AST_Binary, self, {
                operator: "&&",
                left: booleanize(self.condition.negate(compressor)),
                right: self.alternative
            });
        }
        if (is_true(self.alternative)) {
            // c ? x : true ---> !c || x
            return make_node(AST_Binary, self, {
                operator: "||",
                left: booleanize(self.condition.negate(compressor)),
                right: self.consequent
            });
        }
        if (is_false(self.alternative)) {
            // c ? x : false ---> !!c && x
            return make_node(AST_Binary, self, {
                operator: "&&",
                left: booleanize(self.condition),
                right: self.consequent
            });
        }

        return self;

        function booleanize(node) {
            if (node.is_boolean()) return node;
            // !!expression
            return make_node(AST_UnaryPrefix, node, {
                operator: "!",
                expression: node.negate(compressor)
            });
        }

        // AST_True or !0
        function is_true(node) {
            return node instanceof AST_True
                || (node instanceof AST_UnaryPrefix
                && node.operator == "!"
                && node.expression instanceof AST_Constant
                && !node.expression.value);
        }

        // AST_False or !1
        function is_false(node) {
            return node instanceof AST_False
                || (node instanceof AST_UnaryPrefix
                && node.operator == "!"
                && node.expression instanceof AST_Constant
                && !!node.expression.value);
        }
    });

    OPT(AST_Boolean, function (self, compressor) {
        if (compressor.option("booleans")) {
            var p = compressor.parent();
            if (p instanceof AST_Binary && (p.operator == "=="
                || p.operator == "!=")) {
                compressor.warn("Non-strict equality against boolean: {operator} {value} [{file}:{line},{col}]", {
                    operator: p.operator,
                    value: self.value,
                    file: p.start.file,
                    line: p.start.line,
                    col: p.start.col,
                });
                return make_node(AST_Number, self, {
                    value: +self.value
                });
            }
            return make_node(AST_UnaryPrefix, self, {
                operator: "!",
                expression: make_node(AST_Number, self, {
                    value: 1 - self.value
                })
            });
        }
        return self;
    });

    OPT(AST_Sub, function (self, compressor) {
        var prop = self.property;
        if (prop instanceof AST_String && compressor.option("properties")) {
            prop = prop.getValue();
            if (is_identifier_string(prop)) {
                return make_node(AST_Dot, self, {
                    expression: self.expression,
                    property: prop
                }).optimize(compressor);
            }
            var v = parseFloat(prop);
            if (!isNaN(v) && v.toString() == prop) {
                self.property = make_node(AST_Number, self.property, {
                    value: v
                });
            }
        }
        var ev = self.evaluate(compressor);
        if (ev !== self) {
            ev = make_node_from_constant(ev, self).optimize(compressor);
            return best_of(compressor, ev, self);
        }
        return self;
    });

    AST_Lambda.DEFMETHOD("contains_this", function () {
        var result;
        var self = this;
        self.walk(new TreeWalker(function (node) {
            if (result) return true;
            if (node instanceof AST_This) return result = true;
            if (node !== self && node instanceof AST_Scope) return true;
        }));
        return result;
    });

    OPT(AST_Dot, function (self, compressor) {
        var def = self.resolve_defines(compressor);
        if (def) {
            return def.optimize(compressor);
        }
        if (compressor.option("unsafe") && self.expression instanceof AST_Object) {
            var values = self.expression.properties;
            for (var i = values.length; --i >= 0;) {
                if (values[i].key === self.property) {
                    var value = values[i].value;
                    if (value instanceof AST_Function ? !value.contains_this() : !value.has_side_effects(compressor)) {
                        var obj = self.expression.clone();
                        obj.properties = obj.properties.slice();
                        obj.properties.splice(i, 1);
                        return make_sequence(self, [obj, value]).optimize(compressor);
                    }
                }
            }
        }
        if (compressor.option("unsafe_proto")
            && self.expression instanceof AST_Dot
            && self.expression.property == "prototype") {
            var exp = self.expression.expression;
            if (is_undeclared_ref(exp)) switch (exp.name) {
                case "Array":
                    self.expression = make_node(AST_Array, self.expression, {
                        elements: []
                    });
                    break;
                case "Object":
                    self.expression = make_node(AST_Object, self.expression, {
                        properties: []
                    });
                    break;
                case "String":
                    self.expression = make_node(AST_String, self.expression, {
                        value: ""
                    });
                    break;
            }
        }
        var ev = self.evaluate(compressor);
        if (ev !== self) {
            ev = make_node_from_constant(ev, self).optimize(compressor);
            return best_of(compressor, ev, self);
        }
        return self;
    });

    function literals_in_boolean_context(self, compressor) {
        if (compressor.option("booleans") && compressor.in_boolean_context()) {
            return best_of(compressor, self, make_sequence(self, [
                self,
                make_node(AST_True, self)
            ]).optimize(compressor));
        }
        return self;
    };
    OPT(AST_Array, literals_in_boolean_context);
    OPT(AST_Object, literals_in_boolean_context);
    OPT(AST_RegExp, literals_in_boolean_context);

    OPT(AST_Return, function (self, compressor) {
        if (self.value && is_undefined(self.value, compressor)) {
            self.value = null;
        }
        return self;
    });

    OPT(AST_VarDef, function (self, compressor) {
        var defines = compressor.option("global_defs");
        if (defines && HOP(defines, self.name.name)) {
            compressor.warn('global_defs ' + self.name.name + ' redefined [{file}:{line},{col}]', self.start);
        }
        return self;
    });

})();


/************ minify.js **************/

var to_ascii = typeof atob == "undefined" ? function (b64) {
    return new Buffer(b64, "base64").toString();
} : atob;
var to_base64 = typeof btoa == "undefined" ? function (str) {
    return new Buffer(str).toString("base64");
} : btoa;

function read_source_map(code) {
    var match = /\n\/\/# sourceMappingURL=data:application\/json(;.*?)?;base64,(.*)/.exec(code);
    if (!match) {
        AST_Node.warn("inline source map not found");
        return null;
    }
    return to_ascii(match[2]);
}

function set_shorthand(name, options, keys) {
    if (options[name]) {
        keys.forEach(function (key) {
            if (options[key]) {
                if (typeof options[key] != "object") options[key] = {};
                if (!(name in options[key])) options[key][name] = options[name];
            }
        });
    }
}

function init_cache(cache) {
    if (!cache) return;
    if (!("cname" in cache)) cache.cname = -1;
    if (!("props" in cache)) {
        cache.props = new Dictionary();
    } else if (!(cache.props instanceof Dictionary)) {
        cache.props = Dictionary.fromObject(cache.props);
    }
}

function to_json(cache) {
    return {
        cname: cache.cname,
        props: cache.props.toObject()
    };
}

function minifyString(sourceCode, options) {
    options = defaults(options, {
        compress: {},
        ie8: false,
        keep_fnames: false,
        mangle: {},
        nameCache: null,
        output: {},
        parse: {},
        sourceMap: false,
        timings: false,
        toplevel: false,
        warnings: false,
        wrap: false,
    }, true);
    return minify(parse(sourceCode, options.parse), options);
}

function minify(files, options) {
    var warn_function = AST_Node.warn_function;
    try {
        options = defaults(options, {
            compress: {},
            ie8: false,
            keep_fnames: false,
            mangle: {},
            nameCache: null,
            output: {},
            parse: {},
            sourceMap: false,
            timings: false,
            toplevel: false,
            warnings: false,
            wrap: false,
        }, true);
        var timings = options.timings && {
                start: Date.now()
            };
        set_shorthand("ie8", options, ["compress", "mangle", "output"]);
        set_shorthand("keep_fnames", options, ["compress", "mangle"]);
        set_shorthand("toplevel", options, ["compress", "mangle"]);
        set_shorthand("warnings", options, ["compress"]);
        var quoted_props;
        if (options.mangle) {
            options.mangle = defaults(options.mangle, {
                cache: options.nameCache && (options.nameCache.vars || {}),
                eval: false,
                ie8: false,
                keep_fnames: false,
                properties: false,
                reserved: [],
                toplevel: false,
            }, true);
            if (options.mangle.properties) {
                if (typeof options.mangle.properties != "object") {
                    options.mangle.properties = {};
                }
                if (options.mangle.properties.keep_quoted) {
                    quoted_props = options.mangle.properties.reserved;
                    if (!Array.isArray(quoted_props)) quoted_props = [];
                    options.mangle.properties.reserved = quoted_props;
                }
                if (options.nameCache && !("cache" in options.mangle.properties)) {
                    options.mangle.properties.cache = options.nameCache.props || {};
                }
            }
            init_cache(options.mangle.cache);
            init_cache(options.mangle.properties.cache);
        }
        if (options.sourceMap) {
            options.sourceMap = defaults(options.sourceMap, {
                content: null,
                filename: null,
                includeSources: false,
                root: null,
                url: null,
            }, true);
        }
        var warnings = [];
        if (options.warnings && !AST_Node.warn_function) {
            AST_Node.warn_function = function (warning) {
                warnings.push(warning);
            };
        }
        if (timings) timings.parse = Date.now();
        var toplevel;
        if (files instanceof AST_Toplevel) {
            toplevel = files;
        } else {
            if (typeof files == "string") {
                files = [files];
            }
            options.parse = options.parse || {};
            options.parse.toplevel = null;
            for (var name in files) if (HOP(files, name)) {
                options.parse.filename = name;
                options.parse.toplevel = parse(files[name], options.parse);
                if (options.sourceMap && options.sourceMap.content == "inline") {
                    if (Object.keys(files).length > 1)
                        throw new Error("inline source map only works with singular input");
                    options.sourceMap.content = read_source_map(files[name]);
                }
            }
            toplevel = options.parse.toplevel;
        }
        if (quoted_props) {
            reserve_quoted_keys(toplevel, quoted_props);
        }
        if (options.wrap) {
            toplevel = toplevel.wrap_commonjs(options.wrap);
        }
        if (timings) {
            timings.scope1 = Date.now();
        }

        if (options.compress) {
            toplevel.figure_out_scope(options.mangle);
        }
        if (timings) {
            timings.compress = Date.now();
        }
        if (options.compress) {
            toplevel = new Compressor(options.compress).compress(toplevel);
        }
        if (timings) {
            timings.scope2 = Date.now();
        }
        if (options.mangle) {
            toplevel.figure_out_scope(options.mangle);
        }
        if (timings) {
            timings.mangle = Date.now();
        }
        if (options.mangle) {
            base54.reset();
            toplevel.compute_char_frequency(options.mangle);
            toplevel.mangle_names(options.mangle);
        }
        if (timings) {
            timings.properties = Date.now();
        }

        if (options.mangle && options.mangle.properties) {
            toplevel = mangle_properties(toplevel, options.mangle.properties);
        }
        if (timings) {
            timings.output = Date.now();
        }
        var result = {};
        if (options.output.ast) {
            result.ast = toplevel;
        }

        if (!HOP(options.output, "code") || options.output.code) {
            if (options.sourceMap) {
                if (typeof options.sourceMap.content == "string") {
                    options.sourceMap.content = JSON.parse(options.sourceMap.content);
                }
                options.output.source_map = SourceMap({
                    file: options.sourceMap.filename,
                    orig: options.sourceMap.content,
                    root: options.sourceMap.root
                });
                if (options.sourceMap.includeSources) {
                    if (files instanceof AST_Toplevel) {
                        throw new Error("original source content unavailable");
                    } else for (var name in files) if (HOP(files, name)) {
                        options.output.source_map.get().setSourceContent(name, files[name]);
                    }
                }
            }
            delete options.output.ast;
            delete options.output.code;
            var stream = OutputStream(options.output);
            toplevel.print(stream);
            result.code = stream.get();
            if (options.sourceMap) {
                result.map = options.output.source_map.toString();
                if (options.sourceMap.url == "inline") {
                    result.code += "\n//# sourceMappingURL=data:application/json;charset=utf-8;base64," + to_base64(result.map);
                } else if (options.sourceMap.url) {
                    result.code += "\n//# sourceMappingURL=" + options.sourceMap.url;
                }
            }
        }
        if (options.nameCache && options.mangle) {
            if (options.mangle.cache) {
                options.nameCache.vars = to_json(options.mangle.cache);
            }
            if (options.mangle.properties && options.mangle.properties.cache) {
                options.nameCache.props = to_json(options.mangle.properties.cache);
            }
        }
        if (timings) {
            timings.end = Date.now();
            result.timings = {
                parse: 1e-3 * (timings.scope1 - timings.parse),
                scope: 1e-3 * (timings.compress - timings.scope1 + timings.mangle - timings.scope2),
                compress: 1e-3 * (timings.scope2 - timings.compress),
                mangle: 1e-3 * (timings.properties - timings.mangle),
                properties: 1e-3 * (timings.output - timings.properties),
                output: 1e-3 * (timings.end - timings.output),
                total: 1e-3 * (timings.end - timings.start)
            }
        }
        if (warnings.length) {
            result.warnings = warnings;
        }
        return result;
    } catch (ex) {
        return {error: ex};
    } finally {
        AST_Node.warn_function = warn_function;
    }
}


/************ mozilla-ast.js **************/

(function () {

    var normalize_directives = function (body) {
        var in_directive = true;

        for (var i = 0; i < body.length; i++) {
            if (in_directive && body[i] instanceof AST_Statement && body[i].body instanceof AST_String) {
                body[i] = new AST_Directive({
                    start: body[i].start,
                    end: body[i].end,
                    value: body[i].body.value
                });
            } else if (in_directive && !(body[i] instanceof AST_Statement && body[i].body instanceof AST_String)) {
                in_directive = false;
            }
        }

        return body;
    };

    var MOZ_TO_ME = {
        Program: function (M) {
            return new AST_Toplevel({
                start: my_start_token(M),
                end: my_end_token(M),
                body: normalize_directives(M.body.map(from_moz))
            });
        },
        FunctionDeclaration: function (M) {
            return new AST_Defun({
                start: my_start_token(M),
                end: my_end_token(M),
                name: from_moz(M.id),
                argnames: M.params.map(from_moz),
                body: normalize_directives(from_moz(M.body).body)
            });
        },
        FunctionExpression: function (M) {
            return new AST_Function({
                start: my_start_token(M),
                end: my_end_token(M),
                name: from_moz(M.id),
                argnames: M.params.map(from_moz),
                body: normalize_directives(from_moz(M.body).body)
            });
        },
        ExpressionStatement: function (M) {
            return new AST_SimpleStatement({
                start: my_start_token(M),
                end: my_end_token(M),
                body: from_moz(M.expression)
            });
        },
        TryStatement: function (M) {
            var handlers = M.handlers || [M.handler];
            if (handlers.length > 1 || M.guardedHandlers && M.guardedHandlers.length) {
                throw new Error("Multiple catch clauses are not supported.");
            }
            return new AST_Try({
                start: my_start_token(M),
                end: my_end_token(M),
                body: from_moz(M.block).body,
                bcatch: from_moz(handlers[0]),
                bfinally: M.finalizer ? new AST_Finally(from_moz(M.finalizer)) : null
            });
        },
        Property: function (M) {
            var key = M.key;
            var args = {
                start: my_start_token(key),
                end: my_end_token(M.value),
                key: key.type == "Identifier" ? key.name : key.value,
                value: from_moz(M.value)
            };
            if (M.kind == "init") return new AST_ObjectKeyVal(args);
            args.key = new AST_SymbolAccessor({
                name: args.key
            });
            args.value = new AST_Accessor(args.value);
            if (M.kind == "get") return new AST_ObjectGetter(args);
            if (M.kind == "set") return new AST_ObjectSetter(args);
        },
        ArrayExpression: function (M) {
            return new AST_Array({
                start: my_start_token(M),
                end: my_end_token(M),
                elements: M.elements.map(function (elem) {
                    return elem === null ? new AST_Hole() : from_moz(elem);
                })
            });
        },
        ObjectExpression: function (M) {
            return new AST_Object({
                start: my_start_token(M),
                end: my_end_token(M),
                properties: M.properties.map(function (prop) {
                    prop.type = "Property";
                    return from_moz(prop)
                })
            });
        },
        SequenceExpression: function (M) {
            return new AST_Sequence({
                start: my_start_token(M),
                end: my_end_token(M),
                expressions: M.expressions.map(from_moz)
            });
        },
        MemberExpression: function (M) {
            return new (M.computed ? AST_Sub : AST_Dot)({
                start: my_start_token(M),
                end: my_end_token(M),
                property: M.computed ? from_moz(M.property) : M.property.name,
                expression: from_moz(M.object)
            });
        },
        SwitchCase: function (M) {
            return new (M.test ? AST_Case : AST_Default)({
                start: my_start_token(M),
                end: my_end_token(M),
                expression: from_moz(M.test),
                body: M.consequent.map(from_moz)
            });
        },
        VariableDeclaration: function (M) {
            return new AST_Var({
                start: my_start_token(M),
                end: my_end_token(M),
                definitions: M.declarations.map(from_moz)
            });
        },
        Literal: function (M) {
            var val = M.value, args = {
                start: my_start_token(M),
                end: my_end_token(M)
            };
            if (val === null) return new AST_Null(args);
            switch (typeof val) {
                case "string":
                    args.value = val;
                    return new AST_String(args);
                case "number":
                    args.value = val;
                    return new AST_Number(args);
                case "boolean":
                    return new (val ? AST_True : AST_False)(args);
                default:
                    var rx = M.regex;
                    if (rx && rx.pattern) {
                        // RegExpLiteral as per ESTree AST spec
                        args.value = new RegExp(rx.pattern, rx.flags).toString();
                    } else {
                        // support legacy RegExp
                        args.value = M.regex && M.raw ? M.raw : val;
                    }
                    return new AST_RegExp(args);
            }
        },
        Identifier: function (M) {
            var p = FROM_MOZ_STACK[FROM_MOZ_STACK.length - 2];
            return new (  p.type == "LabeledStatement" ? AST_Label
                : p.type == "VariableDeclarator" && p.id === M ? AST_SymbolVar
                    : p.type == "FunctionExpression" ? (p.id === M ? AST_SymbolLambda : AST_SymbolFunarg)
                        : p.type == "FunctionDeclaration" ? (p.id === M ? AST_SymbolDefun : AST_SymbolFunarg)
                            : p.type == "CatchClause" ? AST_SymbolCatch
                                : p.type == "BreakStatement" || p.type == "ContinueStatement" ? AST_LabelRef
                                    : AST_SymbolRef)({
                start: my_start_token(M),
                end: my_end_token(M),
                name: M.name
            });
        }
    };

    MOZ_TO_ME.UpdateExpression =
        MOZ_TO_ME.UnaryExpression = function To_Moz_Unary(M) {
            var prefix = "prefix" in M ? M.prefix
                : M.type == "UnaryExpression" ? true : false;
            return new (prefix ? AST_UnaryPrefix : AST_UnaryPostfix)({
                start: my_start_token(M),
                end: my_end_token(M),
                operator: M.operator,
                expression: from_moz(M.argument)
            });
        };

    map("EmptyStatement", AST_EmptyStatement);
    map("BlockStatement", AST_BlockStatement, "body@body");
    map("IfStatement", AST_If, "test>condition, consequent>body, alternate>alternative");
    map("LabeledStatement", AST_LabeledStatement, "label>label, body>body");
    map("BreakStatement", AST_Break, "label>label");
    map("ContinueStatement", AST_Continue, "label>label");
    map("WithStatement", AST_With, "object>expression, body>body");
    map("SwitchStatement", AST_Switch, "discriminant>expression, cases@body");
    map("ReturnStatement", AST_Return, "argument>value");
    map("ThrowStatement", AST_Throw, "argument>value");
    map("WhileStatement", AST_While, "test>condition, body>body");
    map("DoWhileStatement", AST_Do, "test>condition, body>body");
    map("ForStatement", AST_For, "init>init, test>condition, update>step, body>body");
    map("ForInStatement", AST_ForIn, "left>init, right>object, body>body");
    map("DebuggerStatement", AST_Debugger);
    map("VariableDeclarator", AST_VarDef, "id>name, init>value");
    map("CatchClause", AST_Catch, "param>argname, body%body");

    map("ThisExpression", AST_This);
    map("BinaryExpression", AST_Binary, "operator=operator, left>left, right>right");
    map("LogicalExpression", AST_Binary, "operator=operator, left>left, right>right");
    map("AssignmentExpression", AST_Assign, "operator=operator, left>left, right>right");
    map("ConditionalExpression", AST_Conditional, "test>condition, consequent>consequent, alternate>alternative");
    map("NewExpression", AST_New, "callee>expression, arguments@args");
    map("CallExpression", AST_Call, "callee>expression, arguments@args");

    def_to_moz(AST_Toplevel, function To_Moz_Program(M) {
        return to_moz_scope("Program", M);
    });

    def_to_moz(AST_Defun, function To_Moz_FunctionDeclaration(M) {
        return {
            type: "FunctionDeclaration",
            id: to_moz(M.name),
            params: M.argnames.map(to_moz),
            body: to_moz_scope("BlockStatement", M)
        }
    });

    def_to_moz(AST_Function, function To_Moz_FunctionExpression(M) {
        return {
            type: "FunctionExpression",
            id: to_moz(M.name),
            params: M.argnames.map(to_moz),
            body: to_moz_scope("BlockStatement", M)
        }
    });

    def_to_moz(AST_Directive, function To_Moz_Directive(M) {
        return {
            type: "ExpressionStatement",
            expression: {
                type: "Literal",
                value: M.value
            }
        };
    });

    def_to_moz(AST_SimpleStatement, function To_Moz_ExpressionStatement(M) {
        return {
            type: "ExpressionStatement",
            expression: to_moz(M.body)
        };
    });

    def_to_moz(AST_SwitchBranch, function To_Moz_SwitchCase(M) {
        return {
            type: "SwitchCase",
            test: to_moz(M.expression),
            consequent: M.body.map(to_moz)
        };
    });

    def_to_moz(AST_Try, function To_Moz_TryStatement(M) {
        return {
            type: "TryStatement",
            block: to_moz_block(M),
            handler: to_moz(M.bcatch),
            guardedHandlers: [],
            finalizer: to_moz(M.bfinally)
        };
    });

    def_to_moz(AST_Catch, function To_Moz_CatchClause(M) {
        return {
            type: "CatchClause",
            param: to_moz(M.argname),
            guard: null,
            body: to_moz_block(M)
        };
    });

    def_to_moz(AST_Definitions, function To_Moz_VariableDeclaration(M) {
        return {
            type: "VariableDeclaration",
            kind: "var",
            declarations: M.definitions.map(to_moz)
        };
    });

    def_to_moz(AST_Sequence, function To_Moz_SequenceExpression(M) {
        return {
            type: "SequenceExpression",
            expressions: M.expressions.map(to_moz)
        };
    });

    def_to_moz(AST_PropAccess, function To_Moz_MemberExpression(M) {
        var isComputed = M instanceof AST_Sub;
        return {
            type: "MemberExpression",
            object: to_moz(M.expression),
            computed: isComputed,
            property: isComputed ? to_moz(M.property) : {type: "Identifier", name: M.property}
        };
    });

    def_to_moz(AST_Unary, function To_Moz_Unary(M) {
        return {
            type: M.operator == "++" || M.operator == "--" ? "UpdateExpression" : "UnaryExpression",
            operator: M.operator,
            prefix: M instanceof AST_UnaryPrefix,
            argument: to_moz(M.expression)
        };
    });

    def_to_moz(AST_Binary, function To_Moz_BinaryExpression(M) {
        return {
            type: M.operator == "&&" || M.operator == "||" ? "LogicalExpression" : "BinaryExpression",
            left: to_moz(M.left),
            operator: M.operator,
            right: to_moz(M.right)
        };
    });

    def_to_moz(AST_Array, function To_Moz_ArrayExpression(M) {
        return {
            type: "ArrayExpression",
            elements: M.elements.map(to_moz)
        };
    });

    def_to_moz(AST_Object, function To_Moz_ObjectExpression(M) {
        return {
            type: "ObjectExpression",
            properties: M.properties.map(to_moz)
        };
    });

    def_to_moz(AST_ObjectProperty, function To_Moz_Property(M) {
        var key = {
            type: "Literal",
            value: M.key instanceof AST_SymbolAccessor ? M.key.name : M.key
        };
        var kind;
        if (M instanceof AST_ObjectKeyVal) {
            kind = "init";
        } else if (M instanceof AST_ObjectGetter) {
            kind = "get";
        } else if (M instanceof AST_ObjectSetter) {
            kind = "set";
        }
        return {
            type: "Property",
            kind: kind,
            key: key,
            value: to_moz(M.value)
        };
    });

    def_to_moz(AST_Symbol, function To_Moz_Identifier(M) {
        var def = M.definition();
        return {
            type: "Identifier",
            name: def ? def.mangled_name || def.name : M.name
        };
    });

    def_to_moz(AST_RegExp, function To_Moz_RegExpLiteral(M) {
        var value = M.value;
        return {
            type: "Literal",
            value: value,
            raw: value.toString(),
            regex: {
                pattern: value.source,
                flags: value.toString().match(/[gimuy]*$/)[0]
            }
        };
    });

    def_to_moz(AST_Constant, function To_Moz_Literal(M) {
        var value = M.value;
        if (typeof value === 'number' && (value < 0 || (value === 0 && 1 / value < 0))) {
            return {
                type: "UnaryExpression",
                operator: "-",
                prefix: true,
                argument: {
                    type: "Literal",
                    value: -value,
                    raw: M.start.raw
                }
            };
        }
        return {
            type: "Literal",
            value: value,
            raw: M.start.raw
        };
    });

    def_to_moz(AST_Atom, function To_Moz_Atom(M) {
        return {
            type: "Identifier",
            name: String(M.value)
        };
    });

    AST_Boolean.DEFMETHOD("to_mozilla_ast", AST_Constant.prototype.to_mozilla_ast);
    AST_Null.DEFMETHOD("to_mozilla_ast", AST_Constant.prototype.to_mozilla_ast);
    AST_Hole.DEFMETHOD("to_mozilla_ast", function To_Moz_ArrayHole() {
        return null
    });

    AST_Block.DEFMETHOD("to_mozilla_ast", AST_BlockStatement.prototype.to_mozilla_ast);
    AST_Lambda.DEFMETHOD("to_mozilla_ast", AST_Function.prototype.to_mozilla_ast);

    /* -----[ tools ]----- */

    function raw_token(moznode) {
        if (moznode.type == "Literal") {
            return moznode.raw != null ? moznode.raw : moznode.value + "";
        }
    }

    function my_start_token(moznode) {
        var loc = moznode.loc, start = loc && loc.start;
        var range = moznode.range;
        return new AST_Token({
            file: loc && loc.source,
            line: start && start.line,
            col: start && start.column,
            pos: range ? range[0] : moznode.start,
            endline: start && start.line,
            endcol: start && start.column,
            endpos: range ? range[0] : moznode.start,
            raw: raw_token(moznode),
        });
    };

    function my_end_token(moznode) {
        var loc = moznode.loc, end = loc && loc.end;
        var range = moznode.range;
        return new AST_Token({
            file: loc && loc.source,
            line: end && end.line,
            col: end && end.column,
            pos: range ? range[1] : moznode.end,
            endline: end && end.line,
            endcol: end && end.column,
            endpos: range ? range[1] : moznode.end,
            raw: raw_token(moznode),
        });
    };

    function map(moztype, mytype, propmap) {
        var moz_to_me = "function From_Moz_" + moztype + "(M){\n";
        moz_to_me += "return new U2." + mytype.name + "({\n" +
            "start: my_start_token(M),\n" +
            "end: my_end_token(M)";

        var me_to_moz = "function To_Moz_" + moztype + "(M){\n";
        me_to_moz += "return {\n" +
            "type: " + JSON.stringify(moztype);

        if (propmap) propmap.split(/\s*,\s*/).forEach(function (prop) {
            var m = /([a-z0-9$_]+)(=|@|>|%)([a-z0-9$_]+)/i.exec(prop);
            if (!m) throw new Error("Can't understand property map: " + prop);
            var moz = m[1], how = m[2], my = m[3];
            moz_to_me += ",\n" + my + ": ";
            me_to_moz += ",\n" + moz + ": ";
            switch (how) {
                case "@":
                    moz_to_me += "M." + moz + ".map(from_moz)";
                    me_to_moz += "M." + my + ".map(to_moz)";
                    break;
                case ">":
                    moz_to_me += "from_moz(M." + moz + ")";
                    me_to_moz += "to_moz(M." + my + ")";
                    break;
                case "=":
                    moz_to_me += "M." + moz;
                    me_to_moz += "M." + my;
                    break;
                case "%":
                    moz_to_me += "from_moz(M." + moz + ").body";
                    me_to_moz += "to_moz_block(M)";
                    break;
                default:
                    throw new Error("Can't understand operator in propmap: " + prop);
            }
        });

        moz_to_me += "\n})\n}";
        me_to_moz += "\n}\n}";

        //moz_to_me = parse(moz_to_me).print_to_string({ beautify: true });
        //me_to_moz = parse(me_to_moz).print_to_string({ beautify: true });
        //console.log(moz_to_me);

        moz_to_me = new Function("U2", "my_start_token", "my_end_token", "from_moz", "return(" + moz_to_me + ")")(
            exports, my_start_token, my_end_token, from_moz
        );
        me_to_moz = new Function("to_moz", "to_moz_block", "to_moz_scope", "return(" + me_to_moz + ")")(
            to_moz, to_moz_block, to_moz_scope
        );
        MOZ_TO_ME[moztype] = moz_to_me;
        def_to_moz(mytype, me_to_moz);
    };

    var FROM_MOZ_STACK = null;

    function from_moz(node) {
        FROM_MOZ_STACK.push(node);
        var ret = node != null ? MOZ_TO_ME[node.type](node) : null;
        FROM_MOZ_STACK.pop();
        return ret;
    };

    AST_Node.from_mozilla_ast = function (node) {
        var save_stack = FROM_MOZ_STACK;
        FROM_MOZ_STACK = [];
        var ast = from_moz(node);
        FROM_MOZ_STACK = save_stack;
        return ast;
    };

    function set_moz_loc(mynode, moznode, myparent) {
        var start = mynode.start;
        var end = mynode.end;
        if (start.pos != null && end.endpos != null) {
            moznode.range = [start.pos, end.endpos];
        }
        if (start.line) {
            moznode.loc = {
                start: {line: start.line, column: start.col},
                end: end.endline ? {line: end.endline, column: end.endcol} : null
            };
            if (start.file) {
                moznode.loc.source = start.file;
            }
        }
        return moznode;
    };

    function def_to_moz(mytype, handler) {
        mytype.DEFMETHOD("to_mozilla_ast", function () {
            return set_moz_loc(this, handler(this));
        });
    };

    function to_moz(node) {
        return node != null ? node.to_mozilla_ast() : null;
    };

    function to_moz_block(node) {
        return {
            type: "BlockStatement",
            body: node.body.map(to_moz)
        };
    };

    function to_moz_scope(type, node) {
        var body = node.body.map(to_moz);
        if (node.body[0] instanceof AST_SimpleStatement && node.body[0].body instanceof AST_String) {
            body.unshift(to_moz(new AST_EmptyStatement(node.body[0])));
        }
        return {
            type: type,
            body: body
        };
    };
})();


/********  output.js  *********/

var EXPECT_DIRECTIVE = /^$|[;{][\s\n]*$/;

function is_some_comments(comment) {
    // multiline comment
    return comment.type == "comment2" && /@preserve|@license|@cc_on/i.test(comment.value);
}

function OutputStream(options) {

    options = defaults(options, {
        ascii_only: false,
        beautify: false,
        bracketize: false,
        comments: false,
        ie8: false,
        indent_level: 4,
        indent_start: 0,
        inline_script: true,
        keep_quoted_props: false,
        max_line_len: false,
        preamble: null,
        preserve_line: false,
        quote_keys: false,
        quote_style: 0,
        semicolons: true,
        shebang: true,
        source_map: null,
        webkit: false,
        width: 80,
        wrap_iife: false,
    }, true);

    // Convert comment option to RegExp if neccessary and set up comments filter
    var comment_filter = return_false; // Default case, throw all comments away
    if (options.comments) {
        var comments = options.comments;
        if (typeof options.comments === "string" && /^\/.*\/[a-zA-Z]*$/.test(options.comments)) {
            var regex_pos = options.comments.lastIndexOf("/");
            comments = new RegExp(
                options.comments.substr(1, regex_pos - 1),
                options.comments.substr(regex_pos + 1)
            );
        }
        if (comments instanceof RegExp) {
            comment_filter = function (comment) {
                return comment.type != "comment5" && comments.test(comment.value);
            };
        }
        else if (typeof comments === "function") {
            comment_filter = function (comment) {
                return comment.type != "comment5" && comments(this, comment);
            };
        }
        else if (comments === "some") {
            comment_filter = is_some_comments;
        } else { // NOTE includes "all" option
            comment_filter = return_true;
        }
    }

    var indentation = 0;
    var current_col = 0;
    var current_line = 1;
    var current_pos = 0;
    var OUTPUT = "";

    var to_utf8 = options.ascii_only ? function (str, identifier) {
        return str.replace(/[\u0000-\u001f\u007f-\uffff]/g, function (ch) {
            var code = ch.charCodeAt(0).toString(16);
            if (code.length <= 2 && !identifier) {
                while (code.length < 2) code = "0" + code;
                return "\\x" + code;
            } else {
                while (code.length < 4) code = "0" + code;
                return "\\u" + code;
            }
        });
    } : function (str) {
        return str.replace(/[\ud800-\udbff](?![\udc00-\udfff])/g, function (ch) {
            return "\\u" + ch.charCodeAt(0).toString(16);
        }).replace(/(^|[^\ud800-\udbff])([\udc00-\udfff])/g, function (match, prefix, ch) {
            return prefix + "\\u" + ch.charCodeAt(0).toString(16);
        });
    };

    function make_string(str, quote) {
        var dq = 0, sq = 0;
        str = str.replace(/[\\\b\f\n\r\v\t\x22\x27\u2028\u2029\0\ufeff]/g,
            function (s, i) {
                switch (s) {
                    case '"':
                        ++dq;
                        return '"';
                    case "'":
                        ++sq;
                        return "'";
                    case "\\":
                        return "\\\\";
                    case "\n":
                        return "\\n";
                    case "\r":
                        return "\\r";
                    case "\t":
                        return "\\t";
                    case "\b":
                        return "\\b";
                    case "\f":
                        return "\\f";
                    case "\x0B":
                        return options.ie8 ? "\\x0B" : "\\v";
                    case "\u2028":
                        return "\\u2028";
                    case "\u2029":
                        return "\\u2029";
                    case "\ufeff":
                        return "\\ufeff";
                    case "\0":
                        return /[0-7]/.test(str.charAt(i + 1)) ? "\\x00" : "\\0";
                }
                return s;
            });
        function quote_single() {
            return "'" + str.replace(/\x27/g, "\\'") + "'";
        }

        function quote_double() {
            return '"' + str.replace(/\x22/g, '\\"') + '"';
        }

        str = to_utf8(str);
        switch (options.quote_style) {
            case 1:
                return quote_single();
            case 2:
                return quote_double();
            case 3:
                return quote == "'" ? quote_single() : quote_double();
            default:
                return dq > sq ? quote_single() : quote_double();
        }
    };

    function encode_string(str, quote) {
        var ret = make_string(str, quote);
        if (options.inline_script) {
            ret = ret.replace(/<\x2fscript([>\/\t\n\f\r ])/gi, "<\\/script$1");
            ret = ret.replace(/\x3c!--/g, "\\x3c!--");
            ret = ret.replace(/--\x3e/g, "--\\x3e");
        }
        return ret;
    };

    function make_name(name) {
        name = name.toString();
        name = to_utf8(name, true);
        return name;
    };

    function make_indent(back) {
        return repeat_string(" ", options.indent_start + indentation - back * options.indent_level);
    };

    /* -----[ beautification/minification ]----- */

    var might_need_space = false;
    var might_need_semicolon = false;
    var might_add_newline = 0;
    var last = "";
    var mapping_token, mapping_name, mappings = options.source_map && [];

    var do_add_mapping = mappings ? function () {
        mappings.forEach(function (mapping) {
            try {
                options.source_map.add(
                    mapping.token.file,
                    mapping.line, mapping.col,
                    mapping.token.line, mapping.token.col,
                    !mapping.name && mapping.token.type == "name" ? mapping.token.value : mapping.name
                );
            } catch (ex) {
                AST_Node.warn("Couldn't figure out mapping for {file}:{line},{col} → {cline},{ccol} [{name}]", {
                    file: mapping.token.file,
                    line: mapping.token.line,
                    col: mapping.token.col,
                    cline: mapping.line,
                    ccol: mapping.col,
                    name: mapping.name || ""
                })
            }
        });
        mappings = [];
    } : noop;

    var ensure_line_len = options.max_line_len ? function () {
        if (current_col > options.max_line_len) {
            if (might_add_newline) {
                var left = OUTPUT.slice(0, might_add_newline);
                var right = OUTPUT.slice(might_add_newline);
                if (mappings) {
                    var delta = right.length - current_col;
                    mappings.forEach(function (mapping) {
                        mapping.line++;
                        mapping.col += delta;
                    });
                }
                OUTPUT = left + "\n" + right;
                current_line++;
                current_pos++;
                current_col = right.length;
            }
            if (current_col > options.max_line_len) {
                AST_Node.warn("Output exceeds {max_line_len} characters", options);
            }
        }
        if (might_add_newline) {
            might_add_newline = 0;
            do_add_mapping();
        }
    } : noop;

    var requireSemicolonChars = makePredicate("( [ + * / - , .");

    function print(str) {
        str = String(str);
        var ch = str.charAt(0);
        var prev = last.charAt(last.length - 1);
        if (might_need_semicolon) {
            might_need_semicolon = false;

            if (prev == ":" && ch == "}" || (!ch || ";}".indexOf(ch) < 0) && prev != ";") {
                if (options.semicolons || requireSemicolonChars(ch)) {
                    OUTPUT += ";";
                    current_col++;
                    current_pos++;
                } else {
                    ensure_line_len();
                    OUTPUT += "\n";
                    current_pos++;
                    current_line++;
                    current_col = 0;

                    if (/^\s+$/.test(str)) {
                        // reset the semicolon flag, since we didn't print one
                        // now and might still have to later
                        might_need_semicolon = true;
                    }
                }

                if (!options.beautify)
                    might_need_space = false;
            }
        }

        if (!options.beautify && options.preserve_line && stack[stack.length - 1]) {
            var target_line = stack[stack.length - 1].start.line;
            while (current_line < target_line) {
                ensure_line_len();
                OUTPUT += "\n";
                current_pos++;
                current_line++;
                current_col = 0;
                might_need_space = false;
            }
        }

        if (might_need_space) {
            if ((is_identifier_char(prev)
                && (is_identifier_char(ch) || ch == "\\"))
                || (ch == "/" && ch == prev)
                || ((ch == "+" || ch == "-") && ch == last)) {
                OUTPUT += " ";
                current_col++;
                current_pos++;
            }
            might_need_space = false;
        }

        if (mapping_token) {
            mappings.push({
                token: mapping_token,
                name: mapping_name,
                line: current_line,
                col: current_col
            });
            mapping_token = false;
            if (!might_add_newline) do_add_mapping();
        }

        OUTPUT += str;
        current_pos += str.length;
        var a = str.split(/\r?\n/), n = a.length - 1;
        current_line += n;
        current_col += a[0].length;
        if (n > 0) {
            ensure_line_len();
            current_col = a[n].length;
        }
        last = str;
    };

    var space = options.beautify ? function () {
        print(" ");
    } : function () {
        might_need_space = true;
    };

    var indent = options.beautify ? function (half) {
        if (options.beautify) {
            print(make_indent(half ? 0.5 : 0));
        }
    } : noop;

    var with_indent = options.beautify ? function (col, cont) {
        if (col === true) col = next_indent();
        var save_indentation = indentation;
        indentation = col;
        var ret = cont();
        indentation = save_indentation;
        return ret;
    } : function (col, cont) {
        return cont()
    };

    var newline = options.beautify ? function () {
        print("\n");
    } : options.max_line_len ? function () {
        ensure_line_len();
        might_add_newline = OUTPUT.length;
    } : noop;

    var semicolon = options.beautify ? function () {
        print(";");
    } : function () {
        might_need_semicolon = true;
    };

    function force_semicolon() {
        might_need_semicolon = false;
        print(";");
    };

    function next_indent() {
        return indentation + options.indent_level;
    };

    function with_block(cont) {
        var ret;
        print("{");
        newline();
        with_indent(next_indent(), function () {
            ret = cont();
        });
        indent();
        print("}");
        return ret;
    };

    function with_parens(cont) {
        print("(");
        //XXX: still nice to have that for argument lists
        //var ret = with_indent(current_col, cont);
        var ret = cont();
        print(")");
        return ret;
    };

    function with_square(cont) {
        print("[");
        //var ret = with_indent(current_col, cont);
        var ret = cont();
        print("]");
        return ret;
    };

    function comma() {
        print(",");
        space();
    };

    function colon() {
        print(":");
        space();
    };

    var add_mapping = mappings ? function (token, name) {
        mapping_token = token;
        mapping_name = name;
    } : noop;

    function get() {
        if (might_add_newline) {
            ensure_line_len();
        }
        return OUTPUT;
    };

    var stack = [];
    return {
        get: get,
        toString: get,
        indent: indent,
        indentation: function () {
            return indentation
        },
        current_width: function () {
            return current_col - indentation
        },
        should_break: function () {
            return options.width && this.current_width() >= options.width
        },
        newline: newline,
        print: print,
        space: space,
        comma: comma,
        colon: colon,
        last: function () {
            return last
        },
        semicolon: semicolon,
        force_semicolon: force_semicolon,
        to_utf8: to_utf8,
        print_name: function (name) {
            print(make_name(name))
        },
        print_string: function (str, quote, escape_directive) {
            var encoded = encode_string(str, quote);
            if (escape_directive === true && encoded.indexOf("\\") === -1) {
                // Insert semicolons to break directive prologue
                if (!EXPECT_DIRECTIVE.test(OUTPUT)) {
                    force_semicolon();
                }
                force_semicolon();
            }
            print(encoded);
        },
        encode_string: encode_string,
        next_indent: next_indent,
        with_indent: with_indent,
        with_block: with_block,
        with_parens: with_parens,
        with_square: with_square,
        add_mapping: add_mapping,
        option: function (opt) {
            return options[opt]
        },
        comment_filter: comment_filter,
        line: function () {
            return current_line
        },
        col: function () {
            return current_col
        },
        pos: function () {
            return current_pos
        },
        push_node: function (node) {
            stack.push(node)
        },
        pop_node: function () {
            return stack.pop()
        },
        parent: function (n) {
            return stack[stack.length - 2 - (n || 0)];
        }
    };

};

/* -----[ code generators ]----- */

(function () {

    /* -----[ utils ]----- */

    function DEFPRINT(nodetype, generator) {
        nodetype.DEFMETHOD("_codegen", generator);
    };

    var use_asm = false;
    var in_directive = false;

    AST_Node.DEFMETHOD("print", function (stream, force_parens) {
        var self = this, generator = self._codegen, prev_use_asm = use_asm;
        if (self instanceof AST_Directive && self.value == "use asm" && stream.parent() instanceof AST_Scope) {
            use_asm = true;
        }
        function doit() {
            self.add_comments(stream);
            self.add_source_map(stream);
            generator(self, stream);
        }

        stream.push_node(self);
        if (force_parens || self.needs_parens(stream)) {
            stream.with_parens(doit);
        } else {
            doit();
        }
        stream.pop_node();
        if (self instanceof AST_Scope) {
            use_asm = prev_use_asm;
        }
    });
    AST_Node.DEFMETHOD("_print", AST_Node.prototype.print);

    AST_Node.DEFMETHOD("print_to_string", function (options) {
        var s = OutputStream(options);
        if (!options) s._readonly = true;
        this.print(s);
        return s.get();
    });

    /* -----[ comments ]----- */

    AST_Node.DEFMETHOD("add_comments", function (output) {
        if (output._readonly) return;
        var self = this;
        var start = self.start;
        if (start && !start._comments_dumped) {
            start._comments_dumped = true;
            var comments = start.comments_before || [];

            // XXX: ugly fix for https://github.com/mishoo/UglifyJS2/issues/112
            //               and https://github.com/mishoo/UglifyJS2/issues/372
            if (self instanceof AST_Exit && self.value) {
                self.value.walk(new TreeWalker(function (node) {
                    if (node.start && node.start.comments_before) {
                        comments = comments.concat(node.start.comments_before);
                        node.start.comments_before = [];
                    }
                    if (node instanceof AST_Function ||
                        node instanceof AST_Array ||
                        node instanceof AST_Object) {
                        return true; // don't go inside.
                    }
                }));
            }

            if (output.pos() == 0) {
                if (comments.length > 0 && output.option("shebang") && comments[0].type == "comment5") {
                    output.print("#!" + comments.shift().value + "\n");
                    output.indent();
                }
                var preamble = output.option("preamble");
                if (preamble) {
                    output.print(preamble.replace(/\r\n?|[\n\u2028\u2029]|\s*$/g, "\n"));
                }
            }

            comments = comments.filter(output.comment_filter, self);

            // Keep single line comments after nlb, after nlb
            if (!output.option("beautify") && comments.length > 0 &&
                /comment[134]/.test(comments[0].type) &&
                output.col() !== 0 && comments[0].nlb) {
                output.print("\n");
            }

            comments.forEach(function (c) {
                if (/comment[134]/.test(c.type)) {
                    output.print("//" + c.value + "\n");
                    output.indent();
                }
                else if (c.type == "comment2") {
                    output.print("/*" + c.value + "*/");
                    if (start.nlb) {
                        output.print("\n");
                        output.indent();
                    } else {
                        output.space();
                    }
                }
            });
        }
    });

    /* -----[ PARENTHESES ]----- */

    function PARENS(nodetype, func) {
        if (Array.isArray(nodetype)) {
            nodetype.forEach(function (nodetype) {
                PARENS(nodetype, func);
            });
        } else {
            nodetype.DEFMETHOD("needs_parens", func);
        }
    };

    PARENS(AST_Node, function () {
        return false;
    });

    // a function expression needs parens around it when it's provably
    // the first token to appear in a statement.
    PARENS(AST_Function, function (output) {
        if (first_in_statement(output)) {
            return true;
        }

        if (output.option('webkit')) {
            var p = output.parent();
            if (p instanceof AST_PropAccess && p.expression === this) {
                return true;
            }
        }

        if (output.option('wrap_iife')) {
            var p = output.parent();
            return p instanceof AST_Call && p.expression === this;
        }

        return false;
    });

    // same goes for an object literal, because otherwise it would be
    // interpreted as a block of code.
    PARENS(AST_Object, function (output) {
        return first_in_statement(output);
    });

    PARENS(AST_Unary, function (output) {
        var p = output.parent();
        return p instanceof AST_PropAccess && p.expression === this
            || p instanceof AST_Call && p.expression === this;
    });

    PARENS(AST_Sequence, function (output) {
        var p = output.parent();
        return p instanceof AST_Call             // (foo, bar)() or foo(1, (2, 3), 4)
            || p instanceof AST_Unary            // !(foo, bar, baz)
            || p instanceof AST_Binary           // 1 + (2, 3) + 4 ==> 8
            || p instanceof AST_VarDef           // var a = (1, 2), b = a + a; ==> b == 4
            || p instanceof AST_PropAccess       // (1, {foo:2}).foo or (1, {foo:2})["foo"] ==> 2
            || p instanceof AST_Array            // [ 1, (2, 3), 4 ] ==> [ 1, 3, 4 ]
            || p instanceof AST_ObjectProperty   // { foo: (1, 2) }.foo ==> 2
            || p instanceof AST_Conditional      /* (false, true) ? (a = 10, b = 20) : (c = 30)
         * ==> 20 (side effect, set a := 10 and b := 20) */
            ;
    });

    PARENS(AST_Binary, function (output) {
        var p = output.parent();
        // (foo && bar)()
        if (p instanceof AST_Call && p.expression === this)
            return true;
        // typeof (foo && bar)
        if (p instanceof AST_Unary)
            return true;
        // (foo && bar)["prop"], (foo && bar).prop
        if (p instanceof AST_PropAccess && p.expression === this)
            return true;
        // this deals with precedence: 3 * (2 + 1)
        if (p instanceof AST_Binary) {
            var po = p.operator, pp = PRECEDENCE[po];
            var so = this.operator, sp = PRECEDENCE[so];
            if (pp > sp
                || (pp == sp
                && this === p.right)) {
                return true;
            }
        }
    });

    PARENS(AST_PropAccess, function (output) {
        var p = output.parent();
        if (p instanceof AST_New && p.expression === this) {
            // i.e. new (foo.bar().baz)
            //
            // if there's one call into this subtree, then we need
            // parens around it too, otherwise the call will be
            // interpreted as passing the arguments to the upper New
            // expression.
            var parens = false;
            this.walk(new TreeWalker(function (node) {
                if (parens || node instanceof AST_Scope) return true;
                if (node instanceof AST_Call) {
                    parens = true;
                    return true;
                }
            }));
            return parens;
        }
    });

    PARENS(AST_Call, function (output) {
        var p = output.parent(), p1;
        if (p instanceof AST_New && p.expression === this)
            return true;

        // workaround for Safari bug.
        // https://bugs.webkit.org/show_bug.cgi?id=123506
        return this.expression instanceof AST_Function
            && p instanceof AST_PropAccess
            && p.expression === this
            && (p1 = output.parent(1)) instanceof AST_Assign
            && p1.left === p;
    });

    PARENS(AST_New, function (output) {
        var p = output.parent();
        if (!need_constructor_parens(this, output)
            && (p instanceof AST_PropAccess // (new Date).getTime(), (new Date)["getTime"]()
            || p instanceof AST_Call && p.expression === this)) // (new foo)(bar)
            return true;
    });

    PARENS(AST_Number, function (output) {
        var p = output.parent();
        if (p instanceof AST_PropAccess && p.expression === this) {
            var value = this.getValue();
            if (value < 0 || /^0/.test(make_num(value))) {
                return true;
            }
        }
    });

    PARENS([AST_Assign, AST_Conditional], function (output) {
        var p = output.parent();
        // !(a = false) → true
        if (p instanceof AST_Unary)
            return true;
        // 1 + (a = 2) + 3 → 6, side effect setting a = 2
        if (p instanceof AST_Binary && !(p instanceof AST_Assign))
            return true;
        // (a = func)() —or— new (a = Object)()
        if (p instanceof AST_Call && p.expression === this)
            return true;
        // (a = foo) ? bar : baz
        if (p instanceof AST_Conditional && p.condition === this)
            return true;
        // (a = foo)["prop"] —or— (a = foo).prop
        if (p instanceof AST_PropAccess && p.expression === this)
            return true;
    });

    /* -----[ PRINTERS ]----- */

    DEFPRINT(AST_Directive, function (self, output) {
        output.print_string(self.value, self.quote);
        output.semicolon();
    });
    DEFPRINT(AST_Debugger, function (self, output) {
        output.print("debugger");
        output.semicolon();
    });

    /* -----[ statements ]----- */

    function display_body(body, is_toplevel, output, allow_directives) {
        var last = body.length - 1;
        in_directive = allow_directives;
        body.forEach(function (stmt, i) {
            if (in_directive === true && !(stmt instanceof AST_Directive ||
                    stmt instanceof AST_EmptyStatement ||
                    (stmt instanceof AST_SimpleStatement && stmt.body instanceof AST_String)
                )) {
                in_directive = false;
            }
            if (!(stmt instanceof AST_EmptyStatement)) {
                output.indent();
                stmt.print(output);
                if (!(i == last && is_toplevel)) {
                    output.newline();
                    if (is_toplevel) output.newline();
                }
            }
            if (in_directive === true &&
                stmt instanceof AST_SimpleStatement &&
                stmt.body instanceof AST_String
            ) {
                in_directive = false;
            }
        });
        in_directive = false;
    };

    AST_StatementWithBody.DEFMETHOD("_do_print_body", function (output) {
        force_statement(this.body, output);
    });

    DEFPRINT(AST_Statement, function (self, output) {
        self.body.print(output);
        output.semicolon();
    });
    DEFPRINT(AST_Toplevel, function (self, output) {
        display_body(self.body, true, output, true);
        output.print("");
    });
    DEFPRINT(AST_LabeledStatement, function (self, output) {
        self.label.print(output);
        output.colon();
        self.body.print(output);
    });
    DEFPRINT(AST_SimpleStatement, function (self, output) {
        self.body.print(output);
        output.semicolon();
    });
    function print_bracketed(body, output, allow_directives) {
        if (body.length > 0) output.with_block(function () {
            display_body(body, false, output, allow_directives);
        });
        else output.print("{}");
    };
    DEFPRINT(AST_BlockStatement, function (self, output) {
        print_bracketed(self.body, output);
    });
    DEFPRINT(AST_EmptyStatement, function (self, output) {
        output.semicolon();
    });
    DEFPRINT(AST_Do, function (self, output) {
        output.print("do");
        output.space();
        make_block(self.body, output);
        output.space();
        output.print("while");
        output.space();
        output.with_parens(function () {
            self.condition.print(output);
        });
        output.semicolon();
    });
    DEFPRINT(AST_While, function (self, output) {
        output.print("while");
        output.space();
        output.with_parens(function () {
            self.condition.print(output);
        });
        output.space();
        self._do_print_body(output);
    });
    DEFPRINT(AST_For, function (self, output) {
        output.print("for");
        output.space();
        output.with_parens(function () {
            if (self.init) {
                if (self.init instanceof AST_Definitions) {
                    self.init.print(output);
                } else {
                    parenthesize_for_noin(self.init, output, true);
                }
                output.print(";");
                output.space();
            } else {
                output.print(";");
            }
            if (self.condition) {
                self.condition.print(output);
                output.print(";");
                output.space();
            } else {
                output.print(";");
            }
            if (self.step) {
                self.step.print(output);
            }
        });
        output.space();
        self._do_print_body(output);
    });
    DEFPRINT(AST_ForIn, function (self, output) {
        output.print("for");
        output.space();
        output.with_parens(function () {
            self.init.print(output);
            output.space();
            output.print("in");
            output.space();
            self.object.print(output);
        });
        output.space();
        self._do_print_body(output);
    });
    DEFPRINT(AST_With, function (self, output) {
        output.print("with");
        output.space();
        output.with_parens(function () {
            self.expression.print(output);
        });
        output.space();
        self._do_print_body(output);
    });

    /* -----[ functions ]----- */
    AST_Lambda.DEFMETHOD("_do_print", function (output, nokeyword) {
        var self = this;
        if (!nokeyword) {
            output.print("function");
        }

        //输出函数名
        if (self.name) {
            output.space();
            self.name.print(output);
        }

        //括号和参数列表
        output.with_parens(function () {
            self.argnames.forEach(function (arg, i) {
                if (i) {//除了第一个，后续都输出逗号","，分割参数列表
                    output.comma();
                }
                arg.print(output);
            });
        });

        //空格
        output.space();

        //输出body
        print_bracketed(self.body, output, true);
    });
    DEFPRINT(AST_Lambda, function (self, output) {
        self._do_print(output);
    });

    /* -----[ exits ]----- */
    AST_Exit.DEFMETHOD("_do_print", function (output, kind) {
        output.print(kind);
        if (this.value) {
            output.space();
            this.value.print(output);
        }
        output.semicolon();
    });
    DEFPRINT(AST_Return, function (self, output) {
        self._do_print(output, "return");
    });
    DEFPRINT(AST_Throw, function (self, output) {
        self._do_print(output, "throw");
    });

    /* -----[ loop control ]----- */
    AST_LoopControl.DEFMETHOD("_do_print", function (output, kind) {
        output.print(kind);
        if (this.label) {
            output.space();
            this.label.print(output);
        }
        output.semicolon();
    });
    DEFPRINT(AST_Break, function (self, output) {
        self._do_print(output, "break");
    });
    DEFPRINT(AST_Continue, function (self, output) {
        self._do_print(output, "continue");
    });

    /* -----[ if ]----- */
    function make_then(self, output) {
        var b = self.body;
        if (output.option("bracketize")
            || output.option("ie8") && b instanceof AST_Do)
            return make_block(b, output);
        // The squeezer replaces "block"-s that contain only a single
        // statement with the statement itself; technically, the AST
        // is correct, but this can create problems when we output an
        // IF having an ELSE clause where the THEN clause ends in an
        // IF *without* an ELSE block (then the outer ELSE would refer
        // to the inner IF).  This function checks for this case and
        // adds the block brackets if needed.
        if (!b) return output.force_semicolon();
        while (true) {
            if (b instanceof AST_If) {
                if (!b.alternative) {
                    make_block(self.body, output);
                    return;
                }
                b = b.alternative;
            }
            else if (b instanceof AST_StatementWithBody) {
                b = b.body;
            }
            else break;
        }
        force_statement(self.body, output);
    };
    DEFPRINT(AST_If, function (self, output) {
        output.print("if");
        output.space();
        output.with_parens(function () {
            self.condition.print(output);
        });
        output.space();
        if (self.alternative) {
            make_then(self, output);
            output.space();
            output.print("else");
            output.space();
            if (self.alternative instanceof AST_If)
                self.alternative.print(output);
            else
                force_statement(self.alternative, output);
        } else {
            self._do_print_body(output);
        }
    });

    /* -----[ switch ]----- */
    DEFPRINT(AST_Switch, function (self, output) {
        output.print("switch");
        output.space();
        output.with_parens(function () {
            self.expression.print(output);
        });
        output.space();
        var last = self.body.length - 1;
        if (last < 0) output.print("{}");
        else output.with_block(function () {
            self.body.forEach(function (branch, i) {
                output.indent(true);
                branch.print(output);
                if (i < last && branch.body.length > 0)
                    output.newline();
            });
        });
    });
    AST_SwitchBranch.DEFMETHOD("_do_print_body", function (output) {
        output.newline();
        this.body.forEach(function (stmt) {
            output.indent();
            stmt.print(output);
            output.newline();
        });
    });
    DEFPRINT(AST_Default, function (self, output) {
        output.print("default:");
        self._do_print_body(output);
    });
    DEFPRINT(AST_Case, function (self, output) {
        output.print("case");
        output.space();
        self.expression.print(output);
        output.print(":");
        self._do_print_body(output);
    });

    /* -----[ exceptions ]----- */
    DEFPRINT(AST_Try, function (self, output) {
        output.print("try");
        output.space();
        print_bracketed(self.body, output);
        if (self.bcatch) {
            output.space();
            self.bcatch.print(output);
        }
        if (self.bfinally) {
            output.space();
            self.bfinally.print(output);
        }
    });
    DEFPRINT(AST_Catch, function (self, output) {
        output.print("catch");
        output.space();
        output.with_parens(function () {
            self.argname.print(output);
        });
        output.space();
        print_bracketed(self.body, output);
    });
    DEFPRINT(AST_Finally, function (self, output) {
        output.print("finally");
        output.space();
        print_bracketed(self.body, output);
    });

    /* -----[ var/const ]----- */
    AST_Definitions.DEFMETHOD("_do_print", function (output, kind) {
        output.print(kind);
        output.space();
        this.definitions.forEach(function (def, i) {
            if (i) output.comma();
            def.print(output);
        });
        var p = output.parent();
        var in_for = p instanceof AST_For || p instanceof AST_ForIn;
        var avoid_semicolon = in_for && p.init === this;
        if (!avoid_semicolon)
            output.semicolon();
    });
    DEFPRINT(AST_Var, function (self, output) {
        self._do_print(output, "var");
    });

    function parenthesize_for_noin(node, output, noin) {
        var parens = false;
        // need to take some precautions here:
        //    https://github.com/mishoo/UglifyJS2/issues/60
        if (noin) node.walk(new TreeWalker(function (node) {
            if (parens || node instanceof AST_Scope) return true;
            if (node instanceof AST_Binary && node.operator == "in") {
                parens = true;
                return true;
            }
        }));
        node.print(output, parens);
    };

    DEFPRINT(AST_VarDef, function (self, output) {
        self.name.print(output);
        if (self.value) {
            output.space();
            output.print("=");
            output.space();
            var p = output.parent(1);
            var noin = p instanceof AST_For || p instanceof AST_ForIn;
            parenthesize_for_noin(self.value, output, noin);
        }
    });

    /* -----[ other expressions ]----- */
    DEFPRINT(AST_Call, function (self, output) {
        self.expression.print(output);
        if (self instanceof AST_New && !need_constructor_parens(self, output))
            return;
        if (self.expression instanceof AST_Lambda) {
            output.add_mapping(self.start);
        }
        output.with_parens(function () {
            self.args.forEach(function (expr, i) {
                if (i) output.comma();
                expr.print(output);
            });
        });
    });
    DEFPRINT(AST_New, function (self, output) {
        output.print("new");
        output.space();
        AST_Call.prototype._codegen(self, output);
    });

    AST_Sequence.DEFMETHOD("_do_print", function (output) {
        this.expressions.forEach(function (node, index) {
            if (index > 0) {
                output.comma();
                if (output.should_break()) {
                    output.newline();
                    output.indent();
                }
            }
            node.print(output);
        });
    });
    DEFPRINT(AST_Sequence, function (self, output) {
        self._do_print(output);
        // var p = output.parent();
        // if (p instanceof AST_Statement) {
        //     output.with_indent(output.next_indent(), function(){
        //         self._do_print(output);
        //     });
        // } else {
        //     self._do_print(output);
        // }
    });
    DEFPRINT(AST_Dot, function (self, output) {
        var expr = self.expression;
        expr.print(output);
        var prop = self.property;
        if (output.option("ie8") && RESERVED_WORDS(prop)) {
            output.print("[");
            output.add_mapping(self.end);
            output.print_string(prop);
            output.print("]");
        } else {
            if (expr instanceof AST_Number && expr.getValue() >= 0) {
                if (!/[xa-f.)]/i.test(output.last())) {
                    output.print(".");
                }
            }
            output.print(".");
            // the name after dot would be mapped about here.
            output.add_mapping(self.end);
            output.print_name(prop);
        }
    });
    DEFPRINT(AST_Sub, function (self, output) {
        self.expression.print(output);
        output.print("[");
        self.property.print(output);
        output.print("]");
    });
    DEFPRINT(AST_UnaryPrefix, function (self, output) {
        var op = self.operator;
        output.print(op);
        if (/^[a-z]/i.test(op)
            || (/[+-]$/.test(op)
            && self.expression instanceof AST_UnaryPrefix
            && /^[+-]/.test(self.expression.operator))) {
            output.space();
        }
        self.expression.print(output);
    });
    DEFPRINT(AST_UnaryPostfix, function (self, output) {
        self.expression.print(output);
        output.print(self.operator);
    });
    DEFPRINT(AST_Binary, function (self, output) {
        var op = self.operator;
        self.left.print(output);
        if (op[0] == ">" /* ">>" ">>>" ">" ">=" */
            && self.left instanceof AST_UnaryPostfix
            && self.left.operator == "--") {
            // space is mandatory to avoid outputting -->
            output.print(" ");
        } else {
            // the space is optional depending on "beautify"
            output.space();
        }
        output.print(op);
        if ((op == "<" || op == "<<")
            && self.right instanceof AST_UnaryPrefix
            && self.right.operator == "!"
            && self.right.expression instanceof AST_UnaryPrefix
            && self.right.expression.operator == "--") {
            // space is mandatory to avoid outputting <!--
            output.print(" ");
        } else {
            // the space is optional depending on "beautify"
            output.space();
        }
        self.right.print(output);
    });
    DEFPRINT(AST_Conditional, function (self, output) {
        self.condition.print(output);
        output.space();
        output.print("?");
        output.space();
        self.consequent.print(output);
        output.space();
        output.colon();
        self.alternative.print(output);
    });

    /* -----[ literals ]----- */
    DEFPRINT(AST_Array, function (self, output) {
        output.with_square(function () {
            var a = self.elements, len = a.length;
            if (len > 0) output.space();
            a.forEach(function (exp, i) {
                if (i) output.comma();
                exp.print(output);
                // If the final element is a hole, we need to make sure it
                // doesn't look like a trailing comma, by inserting an actual
                // trailing comma.
                if (i === len - 1 && exp instanceof AST_Hole)
                    output.comma();
            });
            if (len > 0) output.space();
        });
    });
    DEFPRINT(AST_Object, function (self, output) {
        if (self.properties.length > 0) output.with_block(function () {
            self.properties.forEach(function (prop, i) {
                if (i) {
                    output.print(",");
                    output.newline();
                }
                output.indent();
                prop.print(output);
            });
            output.newline();
        });
        else output.print("{}");
    });

    function print_property_name(key, quote, output) {
        if (output.option("quote_keys")) {
            output.print_string(key + "");
        } else if ((typeof key == "number"
            || !output.option("beautify")
            && +key + "" == key)
            && parseFloat(key) >= 0) {
            output.print(make_num(key));
        } else if (RESERVED_WORDS(key) ? !output.option("ie8") : is_identifier_string(key)) {
            if (quote && output.option("keep_quoted_props")) {
                output.print_string(key, quote);
            } else {
                output.print_name(key);
            }
        } else {
            output.print_string(key, quote);
        }
    }

    DEFPRINT(AST_ObjectKeyVal, function (self, output) {
        print_property_name(self.key, self.quote, output);
        output.colon();
        self.value.print(output);
    });
    AST_ObjectProperty.DEFMETHOD("_print_getter_setter", function (type, output) {
        output.print(type);
        output.space();
        print_property_name(this.key.name, this.quote, output);
        this.value._do_print(output, true);
    });
    DEFPRINT(AST_ObjectSetter, function (self, output) {
        self._print_getter_setter("set", output);
    });
    DEFPRINT(AST_ObjectGetter, function (self, output) {
        self._print_getter_setter("get", output);
    });
    DEFPRINT(AST_Symbol, function (self, output) {
        var def = self.definition();
        output.print_name(def ? def.mangled_name || def.name : self.name);
    });
    DEFPRINT(AST_Hole, noop);
    DEFPRINT(AST_This, function (self, output) {
        output.print("this");
    });
    DEFPRINT(AST_Constant, function (self, output) {
        output.print(self.getValue());
    });
    DEFPRINT(AST_String, function (self, output) {
        output.print_string(self.getValue(), self.quote, in_directive);
    });
    DEFPRINT(AST_Number, function (self, output) {
        if (use_asm && self.start && self.start.raw != null) {
            output.print(self.start.raw);
        } else {
            output.print(make_num(self.getValue()));
        }
    });

    DEFPRINT(AST_RegExp, function (self, output) {
        var regexp = self.getValue();
        var str = regexp.toString();
        if (regexp.raw_source) {
            str = "/" + regexp.raw_source + str.slice(str.lastIndexOf("/"));
        }
        str = output.to_utf8(str);
        output.print(str);
        var p = output.parent();
        if (p instanceof AST_Binary && /^in/.test(p.operator) && p.left === self)
            output.print(" ");
    });

    function force_statement(stat, output) {
        if (output.option("bracketize")) {
            make_block(stat, output);
        } else {
            if (!stat || stat instanceof AST_EmptyStatement)
                output.force_semicolon();
            else
                stat.print(output);
        }
    };

    // self should be AST_New.  decide if we want to show parens or not.
    function need_constructor_parens(self, output) {
        // Always print parentheses with arguments
        if (self.args.length > 0) return true;

        return output.option("beautify");
    };

    function best_of(a) {
        var best = a[0], len = best.length;
        for (var i = 1; i < a.length; ++i) {
            if (a[i].length < len) {
                best = a[i];
                len = best.length;
            }
        }
        return best;
    };

    function make_num(num) {
        var str = num.toString(10), a = [str.replace(/^0\./, ".").replace('e+', 'e')], m;
        if (Math.floor(num) === num) {
            if (num >= 0) {
                a.push("0x" + num.toString(16).toLowerCase(), // probably pointless
                    "0" + num.toString(8)); // same.
            } else {
                a.push("-0x" + (-num).toString(16).toLowerCase(), // probably pointless
                    "-0" + (-num).toString(8)); // same.
            }
            if ((m = /^(.*?)(0+)$/.exec(num))) {
                a.push(m[1] + "e" + m[2].length);
            }
        } else if ((m = /^0?\.(0+)(.*)$/.exec(num))) {
            a.push(m[2] + "e-" + (m[1].length + m[2].length),
                str.substr(str.indexOf(".")));
        }
        return best_of(a);
    };

    function make_block(stmt, output) {
        if (!stmt || stmt instanceof AST_EmptyStatement)
            output.print("{}");
        else if (stmt instanceof AST_BlockStatement)
            stmt.print(output);
        else output.with_block(function () {
                output.indent();
                stmt.print(output);
                output.newline();
            });
    };

    /* -----[ source map generators ]----- */

    function DEFMAP(nodetype, generator) {
        nodetype.DEFMETHOD("add_source_map", function (stream) {
            generator(this, stream);
        });
    };

    // We could easily add info for ALL nodes, but it seems to me that
    // would be quite wasteful, hence this noop in the base class.
    DEFMAP(AST_Node, noop);

    function basic_sourcemap_gen(self, output) {
        output.add_mapping(self.start);
    };

    // XXX: I'm not exactly sure if we need it for all of these nodes,
    // or if we should add even more.

    DEFMAP(AST_Directive, basic_sourcemap_gen);
    DEFMAP(AST_Debugger, basic_sourcemap_gen);
    DEFMAP(AST_Symbol, basic_sourcemap_gen);
    DEFMAP(AST_Jump, basic_sourcemap_gen);
    DEFMAP(AST_StatementWithBody, basic_sourcemap_gen);
    DEFMAP(AST_LabeledStatement, noop); // since the label symbol will mark it
    DEFMAP(AST_Lambda, basic_sourcemap_gen);
    DEFMAP(AST_Switch, basic_sourcemap_gen);
    DEFMAP(AST_SwitchBranch, basic_sourcemap_gen);
    DEFMAP(AST_BlockStatement, basic_sourcemap_gen);
    DEFMAP(AST_Toplevel, noop);
    DEFMAP(AST_New, basic_sourcemap_gen);
    DEFMAP(AST_Try, basic_sourcemap_gen);
    DEFMAP(AST_Catch, basic_sourcemap_gen);
    DEFMAP(AST_Finally, basic_sourcemap_gen);
    DEFMAP(AST_Definitions, basic_sourcemap_gen);
    DEFMAP(AST_Constant, basic_sourcemap_gen);
    DEFMAP(AST_ObjectSetter, function (self, output) {
        output.add_mapping(self.start, self.key.name);
    });
    DEFMAP(AST_ObjectGetter, function (self, output) {
        output.add_mapping(self.start, self.key.name);
    });
    DEFMAP(AST_ObjectProperty, function (self, output) {
        output.add_mapping(self.start, self.key);
    });

})();


/************ parse.js ***************/

var KEYWORDS = 'break case catch const continue debugger default delete do else finally for function if in instanceof new return switch throw try typeof var void while with';
var KEYWORDS_ATOM = 'false null true';
var RESERVED_WORDS = 'abstract boolean byte char class double enum export extends final float goto implements import int interface let long native package private protected public short static super synchronized this throws transient volatile yield'
    + " " + KEYWORDS_ATOM + " " + KEYWORDS;
var KEYWORDS_BEFORE_EXPRESSION = 'return new delete throw else case';

KEYWORDS = makePredicate(KEYWORDS);
RESERVED_WORDS = makePredicate(RESERVED_WORDS);
KEYWORDS_BEFORE_EXPRESSION = makePredicate(KEYWORDS_BEFORE_EXPRESSION);
KEYWORDS_ATOM = makePredicate(KEYWORDS_ATOM);

var OPERATOR_CHARS = makePredicate(characters("+-*&%=<>!?|~^"));

var RE_HEX_NUMBER = /^0x[0-9a-f]+$/i;
var RE_OCT_NUMBER = /^0[0-7]+$/;

var OPERATORS = makePredicate([
    "in",
    "instanceof",
    "typeof",
    "new",
    "void",
    "delete",
    "++",
    "--",
    "+",
    "-",
    "!",
    "~",
    "&",
    "|",
    "^",
    "*",
    "/",
    "%",
    ">>",
    "<<",
    ">>>",
    "<",
    ">",
    "<=",
    ">=",
    "==",
    "===",
    "!=",
    "!==",
    "?",
    "=",
    "+=",
    "-=",
    "/=",
    "*=",
    "%=",
    ">>=",
    "<<=",
    ">>>=",
    "|=",
    "^=",
    "&=",
    "&&",
    "||"
]);

var WHITESPACE_CHARS = makePredicate(characters(" \u00a0\n\r\t\f\u000b\u200b\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u2028\u2029\u202f\u205f\u3000\uFEFF"));

var NEWLINE_CHARS = makePredicate(characters("\n\r\u2028\u2029"));

var PUNC_BEFORE_EXPRESSION = makePredicate(characters("[{(,;:"));

var PUNC_CHARS = makePredicate(characters("[]{}(),;:"));

/* -----[ Tokenizer ]----- */

// regexps adapted from http://xregexp.com/plugins/#unicode
var UNICODE = {
    letter: new RegExp("[\\u0041-\\u005A\\u0061-\\u007A\\u00AA\\u00B5\\u00BA\\u00C0-\\u00D6\\u00D8-\\u00F6\\u00F8-\\u02C1\\u02C6-\\u02D1\\u02E0-\\u02E4\\u02EC\\u02EE\\u0370-\\u0374\\u0376\\u0377\\u037A-\\u037D\\u037F\\u0386\\u0388-\\u038A\\u038C\\u038E-\\u03A1\\u03A3-\\u03F5\\u03F7-\\u0481\\u048A-\\u052F\\u0531-\\u0556\\u0559\\u0561-\\u0587\\u05D0-\\u05EA\\u05F0-\\u05F2\\u0620-\\u064A\\u066E\\u066F\\u0671-\\u06D3\\u06D5\\u06E5\\u06E6\\u06EE\\u06EF\\u06FA-\\u06FC\\u06FF\\u0710\\u0712-\\u072F\\u074D-\\u07A5\\u07B1\\u07CA-\\u07EA\\u07F4\\u07F5\\u07FA\\u0800-\\u0815\\u081A\\u0824\\u0828\\u0840-\\u0858\\u08A0-\\u08B2\\u0904-\\u0939\\u093D\\u0950\\u0958-\\u0961\\u0971-\\u0980\\u0985-\\u098C\\u098F\\u0990\\u0993-\\u09A8\\u09AA-\\u09B0\\u09B2\\u09B6-\\u09B9\\u09BD\\u09CE\\u09DC\\u09DD\\u09DF-\\u09E1\\u09F0\\u09F1\\u0A05-\\u0A0A\\u0A0F\\u0A10\\u0A13-\\u0A28\\u0A2A-\\u0A30\\u0A32\\u0A33\\u0A35\\u0A36\\u0A38\\u0A39\\u0A59-\\u0A5C\\u0A5E\\u0A72-\\u0A74\\u0A85-\\u0A8D\\u0A8F-\\u0A91\\u0A93-\\u0AA8\\u0AAA-\\u0AB0\\u0AB2\\u0AB3\\u0AB5-\\u0AB9\\u0ABD\\u0AD0\\u0AE0\\u0AE1\\u0B05-\\u0B0C\\u0B0F\\u0B10\\u0B13-\\u0B28\\u0B2A-\\u0B30\\u0B32\\u0B33\\u0B35-\\u0B39\\u0B3D\\u0B5C\\u0B5D\\u0B5F-\\u0B61\\u0B71\\u0B83\\u0B85-\\u0B8A\\u0B8E-\\u0B90\\u0B92-\\u0B95\\u0B99\\u0B9A\\u0B9C\\u0B9E\\u0B9F\\u0BA3\\u0BA4\\u0BA8-\\u0BAA\\u0BAE-\\u0BB9\\u0BD0\\u0C05-\\u0C0C\\u0C0E-\\u0C10\\u0C12-\\u0C28\\u0C2A-\\u0C39\\u0C3D\\u0C58\\u0C59\\u0C60\\u0C61\\u0C85-\\u0C8C\\u0C8E-\\u0C90\\u0C92-\\u0CA8\\u0CAA-\\u0CB3\\u0CB5-\\u0CB9\\u0CBD\\u0CDE\\u0CE0\\u0CE1\\u0CF1\\u0CF2\\u0D05-\\u0D0C\\u0D0E-\\u0D10\\u0D12-\\u0D3A\\u0D3D\\u0D4E\\u0D60\\u0D61\\u0D7A-\\u0D7F\\u0D85-\\u0D96\\u0D9A-\\u0DB1\\u0DB3-\\u0DBB\\u0DBD\\u0DC0-\\u0DC6\\u0E01-\\u0E30\\u0E32\\u0E33\\u0E40-\\u0E46\\u0E81\\u0E82\\u0E84\\u0E87\\u0E88\\u0E8A\\u0E8D\\u0E94-\\u0E97\\u0E99-\\u0E9F\\u0EA1-\\u0EA3\\u0EA5\\u0EA7\\u0EAA\\u0EAB\\u0EAD-\\u0EB0\\u0EB2\\u0EB3\\u0EBD\\u0EC0-\\u0EC4\\u0EC6\\u0EDC-\\u0EDF\\u0F00\\u0F40-\\u0F47\\u0F49-\\u0F6C\\u0F88-\\u0F8C\\u1000-\\u102A\\u103F\\u1050-\\u1055\\u105A-\\u105D\\u1061\\u1065\\u1066\\u106E-\\u1070\\u1075-\\u1081\\u108E\\u10A0-\\u10C5\\u10C7\\u10CD\\u10D0-\\u10FA\\u10FC-\\u1248\\u124A-\\u124D\\u1250-\\u1256\\u1258\\u125A-\\u125D\\u1260-\\u1288\\u128A-\\u128D\\u1290-\\u12B0\\u12B2-\\u12B5\\u12B8-\\u12BE\\u12C0\\u12C2-\\u12C5\\u12C8-\\u12D6\\u12D8-\\u1310\\u1312-\\u1315\\u1318-\\u135A\\u1380-\\u138F\\u13A0-\\u13F4\\u1401-\\u166C\\u166F-\\u167F\\u1681-\\u169A\\u16A0-\\u16EA\\u16EE-\\u16F8\\u1700-\\u170C\\u170E-\\u1711\\u1720-\\u1731\\u1740-\\u1751\\u1760-\\u176C\\u176E-\\u1770\\u1780-\\u17B3\\u17D7\\u17DC\\u1820-\\u1877\\u1880-\\u18A8\\u18AA\\u18B0-\\u18F5\\u1900-\\u191E\\u1950-\\u196D\\u1970-\\u1974\\u1980-\\u19AB\\u19C1-\\u19C7\\u1A00-\\u1A16\\u1A20-\\u1A54\\u1AA7\\u1B05-\\u1B33\\u1B45-\\u1B4B\\u1B83-\\u1BA0\\u1BAE\\u1BAF\\u1BBA-\\u1BE5\\u1C00-\\u1C23\\u1C4D-\\u1C4F\\u1C5A-\\u1C7D\\u1CE9-\\u1CEC\\u1CEE-\\u1CF1\\u1CF5\\u1CF6\\u1D00-\\u1DBF\\u1E00-\\u1F15\\u1F18-\\u1F1D\\u1F20-\\u1F45\\u1F48-\\u1F4D\\u1F50-\\u1F57\\u1F59\\u1F5B\\u1F5D\\u1F5F-\\u1F7D\\u1F80-\\u1FB4\\u1FB6-\\u1FBC\\u1FBE\\u1FC2-\\u1FC4\\u1FC6-\\u1FCC\\u1FD0-\\u1FD3\\u1FD6-\\u1FDB\\u1FE0-\\u1FEC\\u1FF2-\\u1FF4\\u1FF6-\\u1FFC\\u2071\\u207F\\u2090-\\u209C\\u2102\\u2107\\u210A-\\u2113\\u2115\\u2119-\\u211D\\u2124\\u2126\\u2128\\u212A-\\u212D\\u212F-\\u2139\\u213C-\\u213F\\u2145-\\u2149\\u214E\\u2160-\\u2188\\u2C00-\\u2C2E\\u2C30-\\u2C5E\\u2C60-\\u2CE4\\u2CEB-\\u2CEE\\u2CF2\\u2CF3\\u2D00-\\u2D25\\u2D27\\u2D2D\\u2D30-\\u2D67\\u2D6F\\u2D80-\\u2D96\\u2DA0-\\u2DA6\\u2DA8-\\u2DAE\\u2DB0-\\u2DB6\\u2DB8-\\u2DBE\\u2DC0-\\u2DC6\\u2DC8-\\u2DCE\\u2DD0-\\u2DD6\\u2DD8-\\u2DDE\\u2E2F\\u3005-\\u3007\\u3021-\\u3029\\u3031-\\u3035\\u3038-\\u303C\\u3041-\\u3096\\u309D-\\u309F\\u30A1-\\u30FA\\u30FC-\\u30FF\\u3105-\\u312D\\u3131-\\u318E\\u31A0-\\u31BA\\u31F0-\\u31FF\\u3400-\\u4DB5\\u4E00-\\u9FCC\\uA000-\\uA48C\\uA4D0-\\uA4FD\\uA500-\\uA60C\\uA610-\\uA61F\\uA62A\\uA62B\\uA640-\\uA66E\\uA67F-\\uA69D\\uA6A0-\\uA6EF\\uA717-\\uA71F\\uA722-\\uA788\\uA78B-\\uA78E\\uA790-\\uA7AD\\uA7B0\\uA7B1\\uA7F7-\\uA801\\uA803-\\uA805\\uA807-\\uA80A\\uA80C-\\uA822\\uA840-\\uA873\\uA882-\\uA8B3\\uA8F2-\\uA8F7\\uA8FB\\uA90A-\\uA925\\uA930-\\uA946\\uA960-\\uA97C\\uA984-\\uA9B2\\uA9CF\\uA9E0-\\uA9E4\\uA9E6-\\uA9EF\\uA9FA-\\uA9FE\\uAA00-\\uAA28\\uAA40-\\uAA42\\uAA44-\\uAA4B\\uAA60-\\uAA76\\uAA7A\\uAA7E-\\uAAAF\\uAAB1\\uAAB5\\uAAB6\\uAAB9-\\uAABD\\uAAC0\\uAAC2\\uAADB-\\uAADD\\uAAE0-\\uAAEA\\uAAF2-\\uAAF4\\uAB01-\\uAB06\\uAB09-\\uAB0E\\uAB11-\\uAB16\\uAB20-\\uAB26\\uAB28-\\uAB2E\\uAB30-\\uAB5A\\uAB5C-\\uAB5F\\uAB64\\uAB65\\uABC0-\\uABE2\\uAC00-\\uD7A3\\uD7B0-\\uD7C6\\uD7CB-\\uD7FB\\uF900-\\uFA6D\\uFA70-\\uFAD9\\uFB00-\\uFB06\\uFB13-\\uFB17\\uFB1D\\uFB1F-\\uFB28\\uFB2A-\\uFB36\\uFB38-\\uFB3C\\uFB3E\\uFB40\\uFB41\\uFB43\\uFB44\\uFB46-\\uFBB1\\uFBD3-\\uFD3D\\uFD50-\\uFD8F\\uFD92-\\uFDC7\\uFDF0-\\uFDFB\\uFE70-\\uFE74\\uFE76-\\uFEFC\\uFF21-\\uFF3A\\uFF41-\\uFF5A\\uFF66-\\uFFBE\\uFFC2-\\uFFC7\\uFFCA-\\uFFCF\\uFFD2-\\uFFD7\\uFFDA-\\uFFDC]"),
    digit: new RegExp("[\\u0030-\\u0039\\u0660-\\u0669\\u06F0-\\u06F9\\u07C0-\\u07C9\\u0966-\\u096F\\u09E6-\\u09EF\\u0A66-\\u0A6F\\u0AE6-\\u0AEF\\u0B66-\\u0B6F\\u0BE6-\\u0BEF\\u0C66-\\u0C6F\\u0CE6-\\u0CEF\\u0D66-\\u0D6F\\u0DE6-\\u0DEF\\u0E50-\\u0E59\\u0ED0-\\u0ED9\\u0F20-\\u0F29\\u1040-\\u1049\\u1090-\\u1099\\u17E0-\\u17E9\\u1810-\\u1819\\u1946-\\u194F\\u19D0-\\u19D9\\u1A80-\\u1A89\\u1A90-\\u1A99\\u1B50-\\u1B59\\u1BB0-\\u1BB9\\u1C40-\\u1C49\\u1C50-\\u1C59\\uA620-\\uA629\\uA8D0-\\uA8D9\\uA900-\\uA909\\uA9D0-\\uA9D9\\uA9F0-\\uA9F9\\uAA50-\\uAA59\\uABF0-\\uABF9\\uFF10-\\uFF19]"),
    non_spacing_mark: new RegExp("[\\u0300-\\u036F\\u0483-\\u0487\\u0591-\\u05BD\\u05BF\\u05C1\\u05C2\\u05C4\\u05C5\\u05C7\\u0610-\\u061A\\u064B-\\u065E\\u0670\\u06D6-\\u06DC\\u06DF-\\u06E4\\u06E7\\u06E8\\u06EA-\\u06ED\\u0711\\u0730-\\u074A\\u07A6-\\u07B0\\u07EB-\\u07F3\\u0816-\\u0819\\u081B-\\u0823\\u0825-\\u0827\\u0829-\\u082D\\u0900-\\u0902\\u093C\\u0941-\\u0948\\u094D\\u0951-\\u0955\\u0962\\u0963\\u0981\\u09BC\\u09C1-\\u09C4\\u09CD\\u09E2\\u09E3\\u0A01\\u0A02\\u0A3C\\u0A41\\u0A42\\u0A47\\u0A48\\u0A4B-\\u0A4D\\u0A51\\u0A70\\u0A71\\u0A75\\u0A81\\u0A82\\u0ABC\\u0AC1-\\u0AC5\\u0AC7\\u0AC8\\u0ACD\\u0AE2\\u0AE3\\u0B01\\u0B3C\\u0B3F\\u0B41-\\u0B44\\u0B4D\\u0B56\\u0B62\\u0B63\\u0B82\\u0BC0\\u0BCD\\u0C3E-\\u0C40\\u0C46-\\u0C48\\u0C4A-\\u0C4D\\u0C55\\u0C56\\u0C62\\u0C63\\u0CBC\\u0CBF\\u0CC6\\u0CCC\\u0CCD\\u0CE2\\u0CE3\\u0D41-\\u0D44\\u0D4D\\u0D62\\u0D63\\u0DCA\\u0DD2-\\u0DD4\\u0DD6\\u0E31\\u0E34-\\u0E3A\\u0E47-\\u0E4E\\u0EB1\\u0EB4-\\u0EB9\\u0EBB\\u0EBC\\u0EC8-\\u0ECD\\u0F18\\u0F19\\u0F35\\u0F37\\u0F39\\u0F71-\\u0F7E\\u0F80-\\u0F84\\u0F86\\u0F87\\u0F90-\\u0F97\\u0F99-\\u0FBC\\u0FC6\\u102D-\\u1030\\u1032-\\u1037\\u1039\\u103A\\u103D\\u103E\\u1058\\u1059\\u105E-\\u1060\\u1071-\\u1074\\u1082\\u1085\\u1086\\u108D\\u109D\\u135F\\u1712-\\u1714\\u1732-\\u1734\\u1752\\u1753\\u1772\\u1773\\u17B7-\\u17BD\\u17C6\\u17C9-\\u17D3\\u17DD\\u180B-\\u180D\\u18A9\\u1920-\\u1922\\u1927\\u1928\\u1932\\u1939-\\u193B\\u1A17\\u1A18\\u1A56\\u1A58-\\u1A5E\\u1A60\\u1A62\\u1A65-\\u1A6C\\u1A73-\\u1A7C\\u1A7F\\u1B00-\\u1B03\\u1B34\\u1B36-\\u1B3A\\u1B3C\\u1B42\\u1B6B-\\u1B73\\u1B80\\u1B81\\u1BA2-\\u1BA5\\u1BA8\\u1BA9\\u1C2C-\\u1C33\\u1C36\\u1C37\\u1CD0-\\u1CD2\\u1CD4-\\u1CE0\\u1CE2-\\u1CE8\\u1CED\\u1DC0-\\u1DE6\\u1DFD-\\u1DFF\\u20D0-\\u20DC\\u20E1\\u20E5-\\u20F0\\u2CEF-\\u2CF1\\u2DE0-\\u2DFF\\u302A-\\u302F\\u3099\\u309A\\uA66F\\uA67C\\uA67D\\uA6F0\\uA6F1\\uA802\\uA806\\uA80B\\uA825\\uA826\\uA8C4\\uA8E0-\\uA8F1\\uA926-\\uA92D\\uA947-\\uA951\\uA980-\\uA982\\uA9B3\\uA9B6-\\uA9B9\\uA9BC\\uAA29-\\uAA2E\\uAA31\\uAA32\\uAA35\\uAA36\\uAA43\\uAA4C\\uAAB0\\uAAB2-\\uAAB4\\uAAB7\\uAAB8\\uAABE\\uAABF\\uAAC1\\uABE5\\uABE8\\uABED\\uFB1E\\uFE00-\\uFE0F\\uFE20-\\uFE26]"),
    space_combining_mark: new RegExp("[\\u0903\\u093E-\\u0940\\u0949-\\u094C\\u094E\\u0982\\u0983\\u09BE-\\u09C0\\u09C7\\u09C8\\u09CB\\u09CC\\u09D7\\u0A03\\u0A3E-\\u0A40\\u0A83\\u0ABE-\\u0AC0\\u0AC9\\u0ACB\\u0ACC\\u0B02\\u0B03\\u0B3E\\u0B40\\u0B47\\u0B48\\u0B4B\\u0B4C\\u0B57\\u0BBE\\u0BBF\\u0BC1\\u0BC2\\u0BC6-\\u0BC8\\u0BCA-\\u0BCC\\u0BD7\\u0C01-\\u0C03\\u0C41-\\u0C44\\u0C82\\u0C83\\u0CBE\\u0CC0-\\u0CC4\\u0CC7\\u0CC8\\u0CCA\\u0CCB\\u0CD5\\u0CD6\\u0D02\\u0D03\\u0D3E-\\u0D40\\u0D46-\\u0D48\\u0D4A-\\u0D4C\\u0D57\\u0D82\\u0D83\\u0DCF-\\u0DD1\\u0DD8-\\u0DDF\\u0DF2\\u0DF3\\u0F3E\\u0F3F\\u0F7F\\u102B\\u102C\\u1031\\u1038\\u103B\\u103C\\u1056\\u1057\\u1062-\\u1064\\u1067-\\u106D\\u1083\\u1084\\u1087-\\u108C\\u108F\\u109A-\\u109C\\u17B6\\u17BE-\\u17C5\\u17C7\\u17C8\\u1923-\\u1926\\u1929-\\u192B\\u1930\\u1931\\u1933-\\u1938\\u19B0-\\u19C0\\u19C8\\u19C9\\u1A19-\\u1A1B\\u1A55\\u1A57\\u1A61\\u1A63\\u1A64\\u1A6D-\\u1A72\\u1B04\\u1B35\\u1B3B\\u1B3D-\\u1B41\\u1B43\\u1B44\\u1B82\\u1BA1\\u1BA6\\u1BA7\\u1BAA\\u1C24-\\u1C2B\\u1C34\\u1C35\\u1CE1\\u1CF2\\uA823\\uA824\\uA827\\uA880\\uA881\\uA8B4-\\uA8C3\\uA952\\uA953\\uA983\\uA9B4\\uA9B5\\uA9BA\\uA9BB\\uA9BD-\\uA9C0\\uAA2F\\uAA30\\uAA33\\uAA34\\uAA4D\\uAA7B\\uABE3\\uABE4\\uABE6\\uABE7\\uABE9\\uABEA\\uABEC]"),
    connector_punctuation: new RegExp("[\\u005F\\u203F\\u2040\\u2054\\uFE33\\uFE34\\uFE4D-\\uFE4F\\uFF3F]")
};

function is_letter(code) {
    return (code >= 97 && code <= 122)
        || (code >= 65 && code <= 90)
        || (code >= 0xaa && UNICODE.letter.test(String.fromCharCode(code)));
};

function is_digit(code) {
    return code >= 48 && code <= 57;
};

function is_alphanumeric_char(code) {
    return is_digit(code) || is_letter(code);
};

function is_unicode_digit(code) {
    return UNICODE.digit.test(String.fromCharCode(code));
}

function is_unicode_combining_mark(ch) {
    return UNICODE.non_spacing_mark.test(ch) || UNICODE.space_combining_mark.test(ch);
};

function is_unicode_connector_punctuation(ch) {
    return UNICODE.connector_punctuation.test(ch);
};

function is_identifier(name) {
    return !RESERVED_WORDS(name) && /^[a-z_$][a-z0-9_$]*$/i.test(name);
};

function is_identifier_start(code) {
    return code == 36 || code == 95 || is_letter(code);
};

function is_identifier_char(ch) {
    var code = ch.charCodeAt(0);
    return is_identifier_start(code)
        || is_digit(code)
        || code == 8204 // \u200c: zero-width non-joiner <ZWNJ>
        || code == 8205 // \u200d: zero-width joiner <ZWJ> (in my ECMA-262 PDF, this is also 200c)
        || is_unicode_combining_mark(ch)
        || is_unicode_connector_punctuation(ch)
        || is_unicode_digit(code)
        ;
};

function is_identifier_string(str) {
    return /^[a-z_$][a-z0-9_$]*$/i.test(str);
};

function parse_js_number(num) {
    if (RE_HEX_NUMBER.test(num)) {
        return parseInt(num.substr(2), 16);
    } else if (RE_OCT_NUMBER.test(num)) {
        return parseInt(num.substr(1), 8);
    } else {
        var val = parseFloat(num);
        if (val == num) return val;
    }
};

function JS_Parse_Error(message, filename, line, col, pos) {
    this.message = message;
    this.filename = filename;
    this.line = line;
    this.col = col;
    this.pos = pos;
};
JS_Parse_Error.prototype = Object.create(Error.prototype);
JS_Parse_Error.prototype.constructor = JS_Parse_Error;
JS_Parse_Error.prototype.name = "SyntaxError";
configure_error_stack(JS_Parse_Error);

function js_error(message, filename, line, col, pos) {
    throw new JS_Parse_Error(message, filename, line, col, pos);
};

function is_token(token, type, val) {
    return token.type == type && (val == null || token.value == val);
};

var EX_EOF = {};

function tokenizer($TEXT, filename, html5_comments, shebang) {

    var S = {
        text: $TEXT,
        filename: filename,
        pos: 0,
        tokpos: 0,
        line: 1,
        tokline: 0,
        col: 0,
        tokcol: 0,
        newline_before: false,
        regex_allowed: false,
        comments_before: [],
        directives: {},
        directive_stack: []
    };

    function peek() {
        return S.text.charAt(S.pos);
    };

    function next(signal_eof, in_string) {
        var ch = S.text.charAt(S.pos++);
        if (signal_eof && !ch)
            throw EX_EOF;
        if (NEWLINE_CHARS(ch)) {
            S.newline_before = S.newline_before || !in_string;
            ++S.line;
            S.col = 0;
            if (!in_string && ch == "\r" && peek() == "\n") {
                // treat a \r\n sequence as a single \n
                ++S.pos;
                ch = "\n";
            }
        } else {
            ++S.col;
        }
        return ch;
    };

    function forward(i) {
        while (i-- > 0) next();
    };

    function looking_at(str) {
        return S.text.substr(S.pos, str.length) == str;
    };

    function find_eol() {
        var text = S.text;
        for (var i = S.pos, n = S.text.length; i < n; ++i) {
            var ch = text[i];
            if (NEWLINE_CHARS(ch))
                return i;
        }
        return -1;
    };

    function find(what, signal_eof) {
        var pos = S.text.indexOf(what, S.pos);
        if (signal_eof && pos == -1) throw EX_EOF;
        return pos;
    };

    function start_token() {
        S.tokline = S.line;
        S.tokcol = S.col;
        S.tokpos = S.pos;
    };

    var prev_was_dot = false;

    function token(type, value, is_comment) {
        S.regex_allowed = ((type == "operator" && !UNARY_POSTFIX(value)) ||
        (type == "keyword" && KEYWORDS_BEFORE_EXPRESSION(value)) ||
        (type == "punc" && PUNC_BEFORE_EXPRESSION(value)));
        if (type == "punc" && value == ".") {
            prev_was_dot = true;
        } else if (!is_comment) {
            prev_was_dot = false;
        }
        var ret = {
            type: type,
            value: value,
            line: S.tokline,
            col: S.tokcol,
            pos: S.tokpos,
            endline: S.line,
            endcol: S.col,
            endpos: S.pos,
            nlb: S.newline_before,
            file: filename
        };
        if (/^(?:num|string|regexp)$/i.test(type)) {
            ret.raw = $TEXT.substring(ret.pos, ret.endpos);
        }
        if (!is_comment) {
            ret.comments_before = S.comments_before;
            S.comments_before = [];
            // make note of any newlines in the comments that came before
            for (var i = 0, len = ret.comments_before.length; i < len; i++) {
                ret.nlb = ret.nlb || ret.comments_before[i].nlb;
            }
        }
        S.newline_before = false;
        return new AST_Token(ret);
    };

    function skip_whitespace() {
        while (WHITESPACE_CHARS(peek()))
            next();
    };

    function read_while(pred) {
        var ret = "", ch, i = 0;
        while ((ch = peek()) && pred(ch, i++))
            ret += next();
        return ret;
    };

    function parse_error(err) {
        js_error(err, filename, S.tokline, S.tokcol, S.tokpos);
    };

    function read_num(prefix) {
        var has_e = false, after_e = false, has_x = false, has_dot = prefix == ".";
        var num = read_while(function (ch, i) {
            var code = ch.charCodeAt(0);
            switch (code) {
                case 120:
                case 88: // xX
                    return has_x ? false : (has_x = true);
                case 101:
                case 69: // eE
                    return has_x ? true : has_e ? false : (has_e = after_e = true);
                case 45: // -
                    return after_e || (i == 0 && !prefix);
                case 43: // +
                    return after_e;
                case (after_e = false, 46): // .
                    return (!has_dot && !has_x && !has_e) ? (has_dot = true) : false;
            }
            return is_alphanumeric_char(code);
        });
        if (prefix) num = prefix + num;
        if (RE_OCT_NUMBER.test(num) && next_token.has_directive("use strict")) {
            parse_error("Legacy octal literals are not allowed in strict mode");
        }
        var valid = parse_js_number(num);
        if (!isNaN(valid)) {
            return token("num", valid);
        } else {
            parse_error("Invalid syntax: " + num);
        }
    };

    function read_escaped_char(in_string) {
        var ch = next(true, in_string);
        switch (ch.charCodeAt(0)) {
            case 110 :
                return "\n";
            case 114 :
                return "\r";
            case 116 :
                return "\t";
            case 98  :
                return "\b";
            case 118 :
                return "\u000b"; // \v
            case 102 :
                return "\f";
            case 120 :
                return String.fromCharCode(hex_bytes(2)); // \x
            case 117 :
                return String.fromCharCode(hex_bytes(4)); // \u
            case 10  :
                return ""; // newline
            case 13  :            // \r
                if (peek() == "\n") { // DOS newline
                    next(true, in_string);
                    return "";
                }
        }
        if (ch >= "0" && ch <= "7")
            return read_octal_escape_sequence(ch);
        return ch;
    };

    function read_octal_escape_sequence(ch) {
        // Read
        var p = peek();
        if (p >= "0" && p <= "7") {
            ch += next(true);
            if (ch[0] <= "3" && (p = peek()) >= "0" && p <= "7")
                ch += next(true);
        }

        // Parse
        if (ch === "0") return "\0";
        if (ch.length > 0 && next_token.has_directive("use strict"))
            parse_error("Legacy octal escape sequences are not allowed in strict mode");
        return String.fromCharCode(parseInt(ch, 8));
    }

    function hex_bytes(n) {
        var num = 0;
        for (; n > 0; --n) {
            var digit = parseInt(next(true), 16);
            if (isNaN(digit))
                parse_error("Invalid hex-character pattern in string");
            num = (num << 4) | digit;
        }
        return num;
    };

    var read_string = with_eof_error("Unterminated string constant", function (quote_char) {
        var quote = next(), ret = "";
        for (; ;) {
            var ch = next(true, true);
            if (ch == "\\") ch = read_escaped_char(true);
            else if (NEWLINE_CHARS(ch)) parse_error("Unterminated string constant");
            else if (ch == quote) break;
            ret += ch;
        }
        var tok = token("string", ret);
        tok.quote = quote_char;
        return tok;
    });

    function skip_line_comment(type) {
        var regex_allowed = S.regex_allowed;
        var i = find_eol(), ret;
        if (i == -1) {
            ret = S.text.substr(S.pos);
            S.pos = S.text.length;
        } else {
            ret = S.text.substring(S.pos, i);
            S.pos = i;
        }
        S.col = S.tokcol + (S.pos - S.tokpos);
        S.comments_before.push(token(type, ret, true));
        S.regex_allowed = regex_allowed;
        return next_token;
    };

    var skip_multiline_comment = with_eof_error("Unterminated multiline comment", function () {
        var regex_allowed = S.regex_allowed;
        var i = find("*/", true);
        var text = S.text.substring(S.pos, i).replace(/\r\n|\r|\u2028|\u2029/g, '\n');
        // update stream position
        forward(text.length /* doesn't count \r\n as 2 char while S.pos - i does */ + 2);
        S.comments_before.push(token("comment2", text, true));
        S.regex_allowed = regex_allowed;
        return next_token;
    });

    function read_name() {
        var backslash = false, name = "", ch, escaped = false, hex;
        while ((ch = peek()) != null) {
            if (!backslash) {
                if (ch == "\\") escaped = backslash = true, next();
                else if (is_identifier_char(ch)) name += next();
                else break;
            }
            else {
                if (ch != "u") parse_error("Expecting UnicodeEscapeSequence -- uXXXX");
                ch = read_escaped_char();
                if (!is_identifier_char(ch)) parse_error("Unicode char: " + ch.charCodeAt(0) + " is not valid in identifier");
                name += ch;
                backslash = false;
            }
        }
        if (KEYWORDS(name) && escaped) {
            hex = name.charCodeAt(0).toString(16).toUpperCase();
            name = "\\u" + "0000".substr(hex.length) + hex + name.slice(1);
        }
        return name;
    };

    var read_regexp = with_eof_error("Unterminated regular expression", function (source) {
        var prev_backslash = false, ch, in_class = false;
        while ((ch = next(true))) if (NEWLINE_CHARS(ch)) {
            parse_error("Unexpected line terminator");
        } else if (prev_backslash) {
            source += "\\" + ch;
            prev_backslash = false;
        } else if (ch == "[") {
            in_class = true;
            source += ch;
        } else if (ch == "]" && in_class) {
            in_class = false;
            source += ch;
        } else if (ch == "/" && !in_class) {
            break;
        } else if (ch == "\\") {
            prev_backslash = true;
        } else {
            source += ch;
        }
        var mods = read_name();
        try {
            var regexp = new RegExp(source, mods);
            regexp.raw_source = source;
            return token("regexp", regexp);
        } catch (e) {
            parse_error(e.message);
        }
    });

    function read_operator(prefix) {
        function grow(op) {
            if (!peek()) return op;
            var bigger = op + peek();
            if (OPERATORS(bigger)) {
                next();
                return grow(bigger);
            } else {
                return op;
            }
        };
        return token("operator", grow(prefix || next()));
    };

    function handle_slash() {
        next();
        switch (peek()) {
            case "/":
                next();
                return skip_line_comment("comment1");
            case "*":
                next();
                return skip_multiline_comment();
        }
        return S.regex_allowed ? read_regexp("") : read_operator("/");
    };

    function handle_dot() {
        next();
        return is_digit(peek().charCodeAt(0))
            ? read_num(".")
            : token("punc", ".");
    };

    function read_word() {
        var word = read_name();
        if (prev_was_dot) return token("name", word);
        return KEYWORDS_ATOM(word) ? token("atom", word)
            : !KEYWORDS(word) ? token("name", word)
                : OPERATORS(word) ? token("operator", word)
                    : token("keyword", word);
    };

    function with_eof_error(eof_error, cont) {
        return function (x) {
            try {
                return cont(x);
            } catch (ex) {
                if (ex === EX_EOF) parse_error(eof_error);
                else throw ex;
            }
        };
    };

    function next_token(force_regexp) {
        if (force_regexp != null)
            return read_regexp(force_regexp);
        if (shebang && S.pos == 0 && looking_at("#!")) {
            start_token();
            forward(2);
            skip_line_comment("comment5");
        }
        for (; ;) {
            skip_whitespace();
            start_token();
            if (html5_comments) {
                if (looking_at("<!--")) {
                    forward(4);
                    skip_line_comment("comment3");
                    continue;
                }
                if (looking_at("-->") && S.newline_before) {
                    forward(3);
                    skip_line_comment("comment4");
                    continue;
                }
            }
            var ch = peek();
            if (!ch) return token("eof");
            var code = ch.charCodeAt(0);
            switch (code) {
                case 34:
                case 39:
                    return read_string(ch);
                case 46:
                    return handle_dot();
                case 47: {
                    var tok = handle_slash();
                    if (tok === next_token) continue;
                    return tok;
                }
            }
            if (is_digit(code)) return read_num();
            if (PUNC_CHARS(ch)) return token("punc", next());
            if (OPERATOR_CHARS(ch)) return read_operator();
            if (code == 92 || is_identifier_start(code)) return read_word();
            break;
        }
        parse_error("Unexpected character '" + ch + "'");
    };

    next_token.context = function (nc) {
        if (nc) S = nc;
        return S;
    };

    next_token.add_directive = function (directive) {
        S.directive_stack[S.directive_stack.length - 1].push(directive);

        if (S.directives[directive] === undefined) {
            S.directives[directive] = 1;
        } else {
            S.directives[directive]++;
        }
    }

    next_token.push_directives_stack = function () {
        S.directive_stack.push([]);
    }

    next_token.pop_directives_stack = function () {
        var directives = S.directive_stack[S.directive_stack.length - 1];

        for (var i = 0; i < directives.length; i++) {
            S.directives[directives[i]]--;
        }

        S.directive_stack.pop();
    }

    next_token.has_directive = function (directive) {
        return S.directives[directive] > 0;
    }

    return next_token;

};

/* -----[ Parser (constants) ]----- */

var UNARY_PREFIX = makePredicate([
    "typeof",
    "void",
    "delete",
    "--",
    "++",
    "!",
    "~",
    "-",
    "+"
]);

var UNARY_POSTFIX = makePredicate(["--", "++"]);

var ASSIGNMENT = makePredicate(["=", "+=", "-=", "/=", "*=", "%=", ">>=", "<<=", ">>>=", "|=", "^=", "&="]);

var PRECEDENCE = (function (a, ret) {
    for (var i = 0; i < a.length; ++i) {
        var b = a[i];
        for (var j = 0; j < b.length; ++j) {
            ret[b[j]] = i + 1;
        }
    }
    return ret;
})(
    [
        ["||"],
        ["&&"],
        ["|"],
        ["^"],
        ["&"],
        ["==", "===", "!=", "!=="],
        ["<", ">", "<=", ">=", "in", "instanceof"],
        [">>", "<<", ">>>"],
        ["+", "-"],
        ["*", "/", "%"]
    ],
    {}
);

var ATOMIC_START_TOKEN = makePredicate(["atom", "num", "string", "regexp", "name"]);

/* -----[ Parser ]----- */

function parse($TEXT, options) {

    options = defaults(options, {
        bare_returns: false,
        expression: false,
        filename: null,
        html5_comments: true,
        shebang: true,
        strict: false,
        toplevel: null,
    }, true);

    var S = {
        input: (typeof $TEXT == "string"
            ? tokenizer($TEXT, options.filename,
                options.html5_comments, options.shebang)
            : $TEXT),
        token: null,
        prev: null,
        peeked: null,
        in_function: 0,
        in_directives: true,
        in_loop: 0,
        labels: []
    };

    S.token = next();

    function is(type, value) {
        return is_token(S.token, type, value);
    };

    function peek() {
        return S.peeked || (S.peeked = S.input());
    };

    function next() {
        S.prev = S.token;
        if (S.peeked) {
            S.token = S.peeked;
            S.peeked = null;
        } else {
            S.token = S.input();
        }
        S.in_directives = S.in_directives && (
                S.token.type == "string" || is("punc", ";")
            );
        return S.token;
    };

    function prev() {
        return S.prev;
    };

    function croak(msg, line, col, pos) {
        var ctx = S.input.context();
        js_error(msg,
            ctx.filename,
            line != null ? line : ctx.tokline,
            col != null ? col : ctx.tokcol,
            pos != null ? pos : ctx.tokpos);
    };

    function token_error(token, msg) {
        croak(msg, token.line, token.col);
    };

    function unexpected(token) {
        if (token == null)
            token = S.token;
        token_error(token, "Unexpected token: " + token.type + " (" + token.value + ")");
    };

    function expect_token(type, val) {
        if (is(type, val)) {
            return next();
        }
        token_error(S.token, "Unexpected token " + S.token.type + " «" + S.token.value + "»" + ", expected " + type + " «" + val + "»");
    };

    function expect(punc) {
        return expect_token("punc", punc);
    };

    function can_insert_semicolon() {
        return !options.strict && (
                S.token.nlb || is("eof") || is("punc", "}")
            );
    };

    function semicolon(optional) {
        if (is("punc", ";")) next();
        else if (!optional && !can_insert_semicolon()) unexpected();
    };

    function parenthesised() {
        expect("(");
        var exp = expression(true);
        expect(")");
        return exp;
    };

    function embed_tokens(parser) {
        return function () {
            var start = S.token;
            var expr = parser();
            var end = prev();
            expr.start = start;
            expr.end = end;
            return expr;
        };
    };

    function handle_regexp() {
        if (is("operator", "/") || is("operator", "/=")) {
            S.peeked = null;
            S.token = S.input(S.token.value.substr(1)); // force regexp
        }
    };

    var statement = embed_tokens(function () {
        handle_regexp();
        switch (S.token.type) {
            case "string":
                if (S.in_directives) {
                    var token = peek();
                    if (S.token.raw.indexOf("\\") == -1
                        && (token.nlb
                        || is_token(token, "eof")
                        || is_token(token, "punc", ";")
                        || is_token(token, "punc", "}"))) {
                        S.input.add_directive(S.token.value);
                    } else {
                        S.in_directives = false;
                    }
                }
                var dir = S.in_directives, stat = simple_statement();
                return dir ? new AST_Directive(stat.body) : stat;
            case "num":
            case "regexp":
            case "operator":
            case "atom":
                return simple_statement();

            case "name":
                return is_token(peek(), "punc", ":")
                    ? labeled_statement()
                    : simple_statement();

            case "punc":
                switch (S.token.value) {
                    case "{":
                        return new AST_BlockStatement({
                            start: S.token,
                            body: block_(),
                            end: prev()
                        });
                    case "[":
                    case "(":
                        return simple_statement();
                    case ";":
                        S.in_directives = false;
                        next();
                        return new AST_EmptyStatement();
                    default:
                        unexpected();
                }

            case "keyword":
                switch (S.token.value) {
                    case "break":
                        next();
                        return break_cont(AST_Break);

                    case "continue":
                        next();
                        return break_cont(AST_Continue);

                    case "debugger":
                        next();
                        semicolon();
                        return new AST_Debugger();

                    case "do":
                        next();
                        var body = in_loop(statement);
                        expect_token("keyword", "while");
                        var condition = parenthesised();
                        semicolon(true);
                        return new AST_Do({
                            body: body,
                            condition: condition
                        });

                    case "while":
                        next();
                        return new AST_While({
                            condition: parenthesised(),
                            body: in_loop(statement)
                        });

                    case "for":
                        next();
                        return for_();

                    case "function":
                        next();
                        return function_(AST_Defun);

                    case "if":
                        next();
                        return if_();

                    case "return":
                        if (S.in_function == 0 && !options.bare_returns)
                            croak("'return' outside of function");
                        next();
                        var value = null;
                        if (is("punc", ";")) {
                            next();
                        } else if (!can_insert_semicolon()) {
                            value = expression(true);
                            semicolon();
                        }
                        return new AST_Return({
                            value: value
                        });

                    case "switch":
                        next();
                        return new AST_Switch({
                            expression: parenthesised(),
                            body: in_loop(switch_body_)
                        });

                    case "throw":
                        next();
                        if (S.token.nlb)
                            croak("Illegal newline after 'throw'");
                        var value = expression(true);
                        semicolon();
                        return new AST_Throw({
                            value: value
                        });

                    case "try":
                        next();
                        return try_();

                    case "var":
                        next();
                        var node = var_();
                        semicolon();
                        return node;

                    case "with":
                        if (S.input.has_directive("use strict")) {
                            croak("Strict mode may not include a with statement");
                        }
                        next();
                        return new AST_With({
                            expression: parenthesised(),
                            body: statement()
                        });
                }
        }
        unexpected();
    });

    function labeled_statement() {
        var label = as_symbol(AST_Label);
        if (find_if(function (l) {
                return l.name == label.name
            }, S.labels)) {
            // ECMA-262, 12.12: An ECMAScript program is considered
            // syntactically incorrect if it contains a
            // LabelledStatement that is enclosed by a
            // LabelledStatement with the same Identifier as label.
            croak("Label " + label.name + " defined twice");
        }
        expect(":");
        S.labels.push(label);
        var stat = statement();
        S.labels.pop();
        if (!(stat instanceof AST_IterationStatement)) {
            // check for `continue` that refers to this label.
            // those should be reported as syntax errors.
            // https://github.com/mishoo/UglifyJS2/issues/287
            label.references.forEach(function (ref) {
                if (ref instanceof AST_Continue) {
                    ref = ref.label.start;
                    croak("Continue label `" + label.name + "` refers to non-IterationStatement.",
                        ref.line, ref.col, ref.pos);
                }
            });
        }
        return new AST_LabeledStatement({body: stat, label: label});
    };

    function simple_statement(tmp) {
        return new AST_SimpleStatement({body: (tmp = expression(true), semicolon(), tmp)});
    };

    function break_cont(type) {
        var label = null, ldef;
        if (!can_insert_semicolon()) {
            label = as_symbol(AST_LabelRef, true);
        }
        if (label != null) {
            ldef = find_if(function (l) {
                return l.name == label.name
            }, S.labels);
            if (!ldef)
                croak("Undefined label " + label.name);
            label.thedef = ldef;
        }
        else if (S.in_loop == 0)
            croak(type.TYPE + " not inside a loop or switch");
        semicolon();
        var stat = new type({label: label});
        if (ldef) ldef.references.push(stat);
        return stat;
    };

    function for_() {
        expect("(");
        var init = null;
        if (!is("punc", ";")) {
            init = is("keyword", "var")
                ? (next(), var_(true))
                : expression(true, true);
            if (is("operator", "in")) {
                if (init instanceof AST_Var) {
                    if (init.definitions.length > 1)
                        croak("Only one variable declaration allowed in for..in loop", init.start.line, init.start.col, init.start.pos);
                } else if (!is_assignable(init)) {
                    croak("Invalid left-hand side in for..in loop", init.start.line, init.start.col, init.start.pos);
                }
                next();
                return for_in(init);
            }
        }
        return regular_for(init);
    };

    function regular_for(init) {
        expect(";");
        var test = is("punc", ";") ? null : expression(true);
        expect(";");
        var step = is("punc", ")") ? null : expression(true);
        expect(")");
        return new AST_For({
            init: init,
            condition: test,
            step: step,
            body: in_loop(statement)
        });
    };

    function for_in(init) {
        var lhs = init instanceof AST_Var ? init.definitions[0].name : null;
        var obj = expression(true);
        expect(")");
        return new AST_ForIn({
            init: init,
            name: lhs,
            object: obj,
            body: in_loop(statement)
        });
    };

    var function_ = function (ctor) {
        var in_statement = ctor === AST_Defun;
        var name = is("name") ? as_symbol(in_statement ? AST_SymbolDefun : AST_SymbolLambda) : null;
        if (in_statement && !name)
            unexpected();
        expect("(");
        var argnames = [];
        for (var first = true; !is("punc", ")");) {
            if (first) first = false; else expect(",");
            argnames.push(as_symbol(AST_SymbolFunarg));
        }
        next();
        var loop = S.in_loop;
        var labels = S.labels;
        ++S.in_function;
        S.in_directives = true;
        S.input.push_directives_stack();
        S.in_loop = 0;
        S.labels = [];
        var body = block_();
        if (S.input.has_directive("use strict")) {
            if (name) strict_verify_symbol(name);
            argnames.forEach(strict_verify_symbol);
        }
        S.input.pop_directives_stack();
        --S.in_function;
        S.in_loop = loop;
        S.labels = labels;
        return new ctor({
            name: name,
            argnames: argnames,
            body: body
        });
    };

    function if_() {
        var cond = parenthesised(), body = statement(), belse = null;
        if (is("keyword", "else")) {
            next();
            belse = statement();
        }
        return new AST_If({
            condition: cond,
            body: body,
            alternative: belse
        });
    };

    function block_() {
        expect("{");
        var a = [];
        while (!is("punc", "}")) {
            if (is("eof")) unexpected();
            a.push(statement());
        }
        next();
        return a;
    };

    function switch_body_() {
        expect("{");
        var a = [], cur = null, branch = null, tmp;
        while (!is("punc", "}")) {
            if (is("eof")) unexpected();
            if (is("keyword", "case")) {
                if (branch) branch.end = prev();
                cur = [];
                branch = new AST_Case({
                    start: (tmp = S.token, next(), tmp),
                    expression: expression(true),
                    body: cur
                });
                a.push(branch);
                expect(":");
            }
            else if (is("keyword", "default")) {
                if (branch) branch.end = prev();
                cur = [];
                branch = new AST_Default({
                    start: (tmp = S.token, next(), expect(":"), tmp),
                    body: cur
                });
                a.push(branch);
            }
            else {
                if (!cur) unexpected();
                cur.push(statement());
            }
        }
        if (branch) branch.end = prev();
        next();
        return a;
    };

    function try_() {
        var body = block_(), bcatch = null, bfinally = null;
        if (is("keyword", "catch")) {
            var start = S.token;
            next();
            expect("(");
            var name = as_symbol(AST_SymbolCatch);
            expect(")");
            bcatch = new AST_Catch({
                start: start,
                argname: name,
                body: block_(),
                end: prev()
            });
        }
        if (is("keyword", "finally")) {
            var start = S.token;
            next();
            bfinally = new AST_Finally({
                start: start,
                body: block_(),
                end: prev()
            });
        }
        if (!bcatch && !bfinally)
            croak("Missing catch/finally blocks");
        return new AST_Try({
            body: body,
            bcatch: bcatch,
            bfinally: bfinally
        });
    };

    function vardefs(no_in) {
        var a = [];
        for (; ;) {
            a.push(new AST_VarDef({
                start: S.token,
                name: as_symbol(AST_SymbolVar),
                value: is("operator", "=") ? (next(), expression(false, no_in)) : null,
                end: prev()
            }));
            if (!is("punc", ","))
                break;
            next();
        }
        return a;
    };

    var var_ = function (no_in) {
        return new AST_Var({
            start: prev(),
            definitions: vardefs(no_in),
            end: prev()
        });
    };

    var new_ = function (allow_calls) {
        var start = S.token;
        expect_token("operator", "new");
        var newexp = expr_atom(false), args;
        if (is("punc", "(")) {
            next();
            args = expr_list(")");
        } else {
            args = [];
        }
        return subscripts(new AST_New({
            start: start,
            expression: newexp,
            args: args,
            end: prev()
        }), allow_calls);
    };

    function as_atom_node() {
        var tok = S.token, ret;
        switch (tok.type) {
            case "name":
                ret = _make_symbol(AST_SymbolRef);
                break;
            case "num":
                ret = new AST_Number({start: tok, end: tok, value: tok.value});
                break;
            case "string":
                ret = new AST_String({
                    start: tok,
                    end: tok,
                    value: tok.value,
                    quote: tok.quote
                });
                break;
            case "regexp":
                ret = new AST_RegExp({start: tok, end: tok, value: tok.value});
                break;
            case "atom":
                switch (tok.value) {
                    case "false":
                        ret = new AST_False({start: tok, end: tok});
                        break;
                    case "true":
                        ret = new AST_True({start: tok, end: tok});
                        break;
                    case "null":
                        ret = new AST_Null({start: tok, end: tok});
                        break;
                }
                break;
        }
        next();
        return ret;
    };

    var expr_atom = function (allow_calls) {
        if (is("operator", "new")) {
            return new_(allow_calls);
        }
        var start = S.token;
        if (is("punc")) {
            switch (start.value) {
                case "(":
                    next();
                    var ex = expression(true);
                    ex.start = start;
                    ex.end = S.token;
                    expect(")");
                    return subscripts(ex, allow_calls);
                case "[":
                    return subscripts(array_(), allow_calls);
                case "{":
                    return subscripts(object_(), allow_calls);
            }
            unexpected();
        }
        if (is("keyword", "function")) {
            next();
            var func = function_(AST_Function);
            func.start = start;
            func.end = prev();
            return subscripts(func, allow_calls);
        }
        if (ATOMIC_START_TOKEN(S.token.type)) {
            return subscripts(as_atom_node(), allow_calls);
        }
        unexpected();
    };

    function expr_list(closing, allow_trailing_comma, allow_empty) {
        var first = true, a = [];
        while (!is("punc", closing)) {
            if (first) first = false; else expect(",");
            if (allow_trailing_comma && is("punc", closing)) break;
            if (is("punc", ",") && allow_empty) {
                a.push(new AST_Hole({start: S.token, end: S.token}));
            } else {
                a.push(expression(false));
            }
        }
        next();
        return a;
    };

    var array_ = embed_tokens(function () {
        expect("[");
        return new AST_Array({
            elements: expr_list("]", !options.strict, true)
        });
    });

    var create_accessor = embed_tokens(function () {
        return function_(AST_Accessor);
    });

    var object_ = embed_tokens(function () {
        expect("{");
        var first = true, a = [];
        while (!is("punc", "}")) {
            if (first) first = false; else expect(",");
            if (!options.strict && is("punc", "}"))
            // allow trailing comma
                break;
            var start = S.token;
            var type = start.type;
            var name = as_property_name();
            if (type == "name" && !is("punc", ":")) {
                var key = new AST_SymbolAccessor({
                    start: S.token,
                    name: as_property_name(),
                    end: prev()
                });
                if (name == "get") {
                    a.push(new AST_ObjectGetter({
                        start: start,
                        key: key,
                        value: create_accessor(),
                        end: prev()
                    }));
                    continue;
                }
                if (name == "set") {
                    a.push(new AST_ObjectSetter({
                        start: start,
                        key: key,
                        value: create_accessor(),
                        end: prev()
                    }));
                    continue;
                }
            }
            expect(":");
            a.push(new AST_ObjectKeyVal({
                start: start,
                quote: start.quote,
                key: name,
                value: expression(false),
                end: prev()
            }));
        }
        next();
        return new AST_Object({properties: a});
    });

    function as_property_name() {
        var tmp = S.token;
        switch (tmp.type) {
            case "operator":
                if (!KEYWORDS(tmp.value)) unexpected();
            case "num":
            case "string":
            case "name":
            case "keyword":
            case "atom":
                next();
                return tmp.value;
            default:
                unexpected();
        }
    };

    function as_name() {
        var tmp = S.token;
        if (tmp.type != "name") unexpected();
        next();
        return tmp.value;
    };

    function _make_symbol(type) {
        var name = S.token.value;
        return new (name == "this" ? AST_This : type)({
            name: String(name),
            start: S.token,
            end: S.token
        });
    };

    function strict_verify_symbol(sym) {
        if (sym.name == "arguments" || sym.name == "eval")
            croak("Unexpected " + sym.name + " in strict mode", sym.start.line, sym.start.col, sym.start.pos);
    }

    function as_symbol(type, noerror) {
        if (!is("name")) {
            if (!noerror) croak("Name expected");
            return null;
        }
        var sym = _make_symbol(type);
        if (S.input.has_directive("use strict") && sym instanceof AST_SymbolDeclaration) {
            strict_verify_symbol(sym);
        }
        next();
        return sym;
    };

    var subscripts = function (expr, allow_calls) {
        var start = expr.start;
        if (is("punc", ".")) {
            next();
            return subscripts(new AST_Dot({
                start: start,
                expression: expr,
                property: as_name(),
                end: prev()
            }), allow_calls);
        }
        if (is("punc", "[")) {
            next();
            var prop = expression(true);
            expect("]");
            return subscripts(new AST_Sub({
                start: start,
                expression: expr,
                property: prop,
                end: prev()
            }), allow_calls);
        }
        if (allow_calls && is("punc", "(")) {
            next();
            return subscripts(new AST_Call({
                start: start,
                expression: expr,
                args: expr_list(")"),
                end: prev()
            }), true);
        }
        return expr;
    };

    var maybe_unary = function (allow_calls) {
        var start = S.token;
        if (is("operator") && UNARY_PREFIX(start.value)) {
            next();
            handle_regexp();
            var ex = make_unary(AST_UnaryPrefix, start, maybe_unary(allow_calls));
            ex.start = start;
            ex.end = prev();
            return ex;
        }
        var val = expr_atom(allow_calls);
        while (is("operator") && UNARY_POSTFIX(S.token.value) && !S.token.nlb) {
            val = make_unary(AST_UnaryPostfix, S.token, val);
            val.start = start;
            val.end = S.token;
            next();
        }
        return val;
    };

    function make_unary(ctor, token, expr) {
        var op = token.value;
        switch (op) {
            case "++":
            case "--":
                if (!is_assignable(expr))
                    croak("Invalid use of " + op + " operator", token.line, token.col, token.pos);
                break;
            case "delete":
                if (expr instanceof AST_SymbolRef && S.input.has_directive("use strict"))
                    croak("Calling delete on expression not allowed in strict mode", expr.start.line, expr.start.col, expr.start.pos);
                break;
        }
        return new ctor({operator: op, expression: expr});
    };

    var expr_op = function (left, min_prec, no_in) {
        var op = is("operator") ? S.token.value : null;
        if (op == "in" && no_in) op = null;
        var prec = op != null ? PRECEDENCE[op] : null;
        if (prec != null && prec > min_prec) {
            next();
            var right = expr_op(maybe_unary(true), prec, no_in);
            return expr_op(new AST_Binary({
                start: left.start,
                left: left,
                operator: op,
                right: right,
                end: right.end
            }), min_prec, no_in);
        }
        return left;
    };

    function expr_ops(no_in) {
        return expr_op(maybe_unary(true), 0, no_in);
    };

    var maybe_conditional = function (no_in) {
        var start = S.token;
        var expr = expr_ops(no_in);
        if (is("operator", "?")) {
            next();
            var yes = expression(false);
            expect(":");
            return new AST_Conditional({
                start: start,
                condition: expr,
                consequent: yes,
                alternative: expression(false, no_in),
                end: prev()
            });
        }
        return expr;
    };

    function is_assignable(expr) {
        return expr instanceof AST_PropAccess || expr instanceof AST_SymbolRef;
    };

    var maybe_assign = function (no_in) {
        var start = S.token;
        var left = maybe_conditional(no_in), val = S.token.value;
        if (is("operator") && ASSIGNMENT(val)) {
            if (is_assignable(left)) {
                next();
                return new AST_Assign({
                    start: start,
                    left: left,
                    operator: val,
                    right: maybe_assign(no_in),
                    end: prev()
                });
            }
            croak("Invalid assignment");
        }
        return left;
    };

    var expression = function (commas, no_in) {
        var start = S.token;
        var exprs = [];
        while (true) {
            exprs.push(maybe_assign(no_in));
            if (!commas || !is("punc", ",")) break;
            next();
            commas = true;
        }
        return exprs.length == 1 ? exprs[0] : new AST_Sequence({
            start: start,
            expressions: exprs,
            end: peek()
        });
    };

    function in_loop(cont) {
        ++S.in_loop;
        var ret = cont();
        --S.in_loop;
        return ret;
    };

    if (options.expression) {
        return expression(true);
    }

    return (function () {
        var start = S.token;
        var body = [];
        S.input.push_directives_stack();
        while (!is("eof"))
            body.push(statement());
        S.input.pop_directives_stack();
        var end = prev();
        var toplevel = options.toplevel;
        if (toplevel) {
            toplevel.body = toplevel.body.concat(body);
            toplevel.end = end;
        } else {
            toplevel = new AST_Toplevel({start: start, body: body, end: end});
        }
        return toplevel;
    })();

};


/************** propmangle.js ****************/
function find_builtins(reserved) {
    // NaN will be included due to Number.NaN
    [
        "null",
        "true",
        "false",
        "Infinity",
        "-Infinity",
        "undefined",
    ].forEach(add);
    [Object, Array, Function, Number,
        String, Boolean, Error, Math,
        Date, RegExp
    ].forEach(function (ctor) {
        Object.getOwnPropertyNames(ctor).map(add);
        if (ctor.prototype) {
            Object.getOwnPropertyNames(ctor.prototype).map(add);
        }
    });
    function add(name) {
        push_uniq(reserved, name);
    }
}

function reserve_quoted_keys(ast, reserved) {
    function add(name) {
        push_uniq(reserved, name);
    }

    ast.walk(new TreeWalker(function (node) {
        if (node instanceof AST_ObjectKeyVal && node.quote) {
            add(node.key);
        } else if (node instanceof AST_Sub) {
            addStrings(node.property, add);
        }
    }));
}

function addStrings(node, add) {
    node.walk(new TreeWalker(function (node) {
        if (node instanceof AST_Sequence) {
            addStrings(node.expressions[node.expressions.length - 1], add);
        } else if (node instanceof AST_String) {
            add(node.value);
        } else if (node instanceof AST_Conditional) {
            addStrings(node.consequent, add);
            addStrings(node.alternative, add);
        }
        return true;
    }));
}

function mangle_properties(ast, options) {
    options = defaults(options, {
        builtins: false,
        cache: null,
        debug: false,
        keep_quoted: false,
        only_cache: false,
        regex: null,
        reserved: null,
    }, true);

    var reserved = options.reserved;
    if (!Array.isArray(reserved)) reserved = [];
    if (!options.builtins) find_builtins(reserved);

    var cache = options.cache;
    if (cache == null) {
        cache = {
            cname: -1,
            props: new Dictionary()
        };
    }

    var regex = options.regex;

    // note debug is either false (disabled), or a string of the debug suffix to use (enabled).
    // note debug may be enabled as an empty string, which is falsey. Also treat passing 'true'
    // the same as passing an empty string.
    var debug = options.debug !== false;
    var debug_name_suffix;
    if (debug) {
        debug_name_suffix = (options.debug === true ? "" : options.debug);
    }

    var names_to_mangle = [];
    var unmangleable = [];

    // step 1: find candidates to mangle
    ast.walk(new TreeWalker(function (node) {
        if (node instanceof AST_ObjectKeyVal) {
            add(node.key);
        }
        else if (node instanceof AST_ObjectProperty) {
            // setter or getter, since KeyVal is handled above
            add(node.key.name);
        }
        else if (node instanceof AST_Dot) {
            add(node.property);
        }
        else if (node instanceof AST_Sub) {
            addStrings(node.property, add);
        }
    }));

    // step 2: transform the tree, renaming properties
    return ast.transform(new TreeTransformer(function (node) {
        if (node instanceof AST_ObjectKeyVal) {
            node.key = mangle(node.key);
        }
        else if (node instanceof AST_ObjectProperty) {
            // setter or getter
            node.key.name = mangle(node.key.name);
        }
        else if (node instanceof AST_Dot) {
            node.property = mangle(node.property);
        }
        else if (!options.keep_quoted && node instanceof AST_Sub) {
            node.property = mangleStrings(node.property);
        }
    }));

    // only function declarations after this line

    function can_mangle(name) {
        if (unmangleable.indexOf(name) >= 0) return false;
        if (reserved.indexOf(name) >= 0) return false;
        if (options.only_cache) {
            return cache.props.has(name);
        }
        if (/^-?[0-9]+(\.[0-9]+)?(e[+-][0-9]+)?$/.test(name)) return false;
        return true;
    }

    function should_mangle(name) {
        if (regex && !regex.test(name)) return false;
        if (reserved.indexOf(name) >= 0) return false;
        return cache.props.has(name)
            || names_to_mangle.indexOf(name) >= 0;
    }

    function add(name) {
        if (can_mangle(name))
            push_uniq(names_to_mangle, name);

        if (!should_mangle(name)) {
            push_uniq(unmangleable, name);
        }
    }

    function mangle(name) {
        if (!should_mangle(name)) {
            return name;
        }

        var mangled = cache.props.get(name);
        if (!mangled) {
            if (debug) {
                // debug mode: use a prefix and suffix to preserve readability, e.g. o.foo -> o._$foo$NNN_.
                var debug_mangled = "_$" + name + "$" + debug_name_suffix + "_";

                if (can_mangle(debug_mangled)) {
                    mangled = debug_mangled;
                }
            }

            // either debug mode is off, or it is on and we could not use the mangled name
            if (!mangled) {
                do {
                    mangled = base54(++cache.cname);
                } while (!can_mangle(mangled));
            }

            cache.props.set(name, mangled);
        }
        return mangled;
    }

    function mangleStrings(node) {
        return node.transform(new TreeTransformer(function (node) {
            if (node instanceof AST_Sequence) {
                var last = node.expressions.length - 1;
                node.expressions[last] = mangleStrings(node.expressions[last]);
            }
            else if (node instanceof AST_String) {
                node.value = mangle(node.value);
            }
            else if (node instanceof AST_Conditional) {
                node.consequent = mangleStrings(node.consequent);
                node.alternative = mangleStrings(node.alternative);
            }
            return node;
        }));
    }
}

/*********  scope.js  *********/


function SymbolDef(scope, index, orig) {
    this.name = orig.name;
    this.orig = [orig];
    this.scope = scope;
    this.references = [];
    this.global = false;
    this.mangled_name = null;
    this.undeclared = false;
    this.index = index;
    this.id = SymbolDef.next_id++;
};

SymbolDef.next_id = 1;

SymbolDef.prototype = {
    unmangleable: function (options) {
        if (!options) options = {};

        return (this.global && !options.toplevel)
            || this.undeclared
            || (!(options['eval']) && (this.scope.uses_eval || this.scope.uses_with))
            || (options.keep_fnames
            && (this.orig[0] instanceof AST_SymbolLambda
            || this.orig[0] instanceof AST_SymbolDefun));
    },
    mangle: function (options) {
        var cache = options.cache && options.cache.props;
        if (this.global && cache && cache.has(this.name)) {
            this.mangled_name = cache.get(this.name);
        }
        else if (!this.mangled_name && !this.unmangleable(options)) {
            var s = this.scope;
            var sym = this.orig[0];
            if (options.ie8 && sym instanceof AST_SymbolLambda)
                s = s.parent_scope;
            var def;
            if (def = this.redefined()) {
                this.mangled_name = def.mangled_name || def.name;
            } else {
                this.mangled_name = s.next_mangled(options, this);
            }
            if (this.global && cache) {
                cache.set(this.name, this.mangled_name);
            }
        }
    },
    redefined: function () {
        return this.defun && this.defun.variables.get(this.name);
    }
};

AST_Toplevel.DEFMETHOD("figure_out_scope", function (options) {
    options = defaults(options, {
        cache: null,
        ie8: false,
    });

    // pass 1: setup scope chaining and handle definitions
    var self = this;
    var scope = self.parent_scope = null;
    var labels = new Dictionary();
    var defun = null;
    var tw = new TreeWalker(function (node, descend) {
        if (node instanceof AST_Catch) {
            var save_scope = scope;
            scope = new AST_Scope(node);
            scope.init_scope_vars(save_scope);
            descend();
            scope = save_scope;
            return true;
        }
        if (node instanceof AST_Scope) {
            node.init_scope_vars(scope);
            var save_scope = scope;
            var save_defun = defun;
            var save_labels = labels;
            defun = scope = node;
            labels = new Dictionary();
            descend();
            scope = save_scope;
            defun = save_defun;
            labels = save_labels;
            return true;        // don't descend again in TreeWalker
        }
        if (node instanceof AST_LabeledStatement) {
            var l = node.label;
            if (labels.has(l.name)) {
                throw new Error(string_template("Label {name} defined twice", l));
            }
            labels.set(l.name, l);
            descend();
            labels.del(l.name);
            return true;        // no descend again
        }
        if (node instanceof AST_With) {
            for (var s = scope; s; s = s.parent_scope)
                s.uses_with = true;
            return;
        }
        if (node instanceof AST_Symbol) {
            node.scope = scope;
        }
        if (node instanceof AST_Label) {
            node.thedef = node;
            node.references = [];
        }
        if (node instanceof AST_SymbolLambda) {
            defun.def_function(node);
        }
        else if (node instanceof AST_SymbolDefun) {
            // Careful here, the scope where this should be defined is
            // the parent scope.  The reason is that we enter a new
            // scope when we encounter the AST_Defun node (which is
            // instanceof AST_Scope) but we get to the symbol a bit
            // later.
            (node.scope = defun.parent_scope).def_function(node);
        }
        else if (node instanceof AST_SymbolVar) {
            defun.def_variable(node);
            if (defun !== scope) {
                node.mark_enclosed(options);
                var def = scope.find_variable(node);
                if (node.thedef !== def) {
                    node.thedef = def;
                    node.reference(options);
                }
            }
        }
        else if (node instanceof AST_SymbolCatch) {
            scope.def_variable(node).defun = defun;
        }
        else if (node instanceof AST_LabelRef) {
            var sym = labels.get(node.name);
            if (!sym) throw new Error(string_template("Undefined label {name} [{line},{col}]", {
                name: node.name,
                line: node.start.line,
                col: node.start.col
            }));
            node.thedef = sym;
        }
    });
    self.walk(tw);

    // pass 2: find back references and eval
    self.globals = new Dictionary();
    var tw = new TreeWalker(function (node, descend) {
        if (node instanceof AST_LoopControl && node.label) {
            node.label.thedef.references.push(node);
            return true;
        }
        if (node instanceof AST_SymbolRef) {
            var name = node.name;
            if (name == "eval" && tw.parent() instanceof AST_Call) {
                for (var s = node.scope; s && !s.uses_eval; s = s.parent_scope) {
                    s.uses_eval = true;
                }
            }
            var sym = node.scope.find_variable(name);
            if (!sym) {
                sym = self.def_global(node);
            } else if (sym.scope instanceof AST_Lambda && name == "arguments") {
                sym.scope.uses_arguments = true;
            }
            node.thedef = sym;
            node.reference(options);
            return true;
        }
        // ensure mangling works if catch reuses a scope variable
        var def;
        if (node instanceof AST_SymbolCatch && (def = node.definition().redefined())) {
            var s = node.scope;
            while (s) {
                push_uniq(s.enclosed, def);
                if (s === def.scope) break;
                s = s.parent_scope;
            }
        }
    });
    self.walk(tw);

    // pass 3: fix up any scoping issue with IE8
    if (options.ie8) {
        self.walk(new TreeWalker(function (node, descend) {
            if (node instanceof AST_SymbolCatch) {
                var name = node.name;
                var refs = node.thedef.references;
                var scope = node.thedef.defun;
                var def = scope.find_variable(name) || self.globals.get(name) || scope.def_variable(node);
                refs.forEach(function (ref) {
                    ref.thedef = def;
                    ref.reference(options);
                });
                node.thedef = def;
                node.reference(options);
                return true;
            }
        }));
    }

    if (options.cache) {
        this.cname = options.cache.cname;
    }
});

AST_Toplevel.DEFMETHOD("def_global", function (node) {
    var globals = this.globals, name = node.name;
    if (globals.has(name)) {
        return globals.get(name);
    } else {
        var g = new SymbolDef(this, globals.size(), node);
        g.undeclared = true;
        g.global = true;
        globals.set(name, g);
        return g;
    }
});

AST_Scope.DEFMETHOD("init_scope_vars", function (parent_scope) {
    this.variables = new Dictionary();  // map name to AST_SymbolVar (variables defined in this scope; includes functions)
    this.functions = new Dictionary();  // map name to AST_SymbolDefun (functions defined in this scope)
    this.uses_with = false;             // will be set to true if this or some nested scope uses the `with` statement
    this.uses_eval = false;             // will be set to true if this or nested scope uses the global `eval`
    this.parent_scope = parent_scope;   // the parent scope
    this.enclosed = [];                 // a list of variables from this or outer scope(s) that are referenced from this or inner scopes
    this.cname = -1;                    // the current index for mangling functions/variables
});

AST_Lambda.DEFMETHOD("init_scope_vars", function () {
    AST_Scope.prototype.init_scope_vars.apply(this, arguments);
    this.uses_arguments = false;
    this.def_variable(new AST_SymbolFunarg({
        name: "arguments",
        start: this.start,
        end: this.end
    }));
});

AST_Symbol.DEFMETHOD("mark_enclosed", function (options) {
    var def = this.definition();
    var s = this.scope;
    while (s) {
        push_uniq(s.enclosed, def);
        if (options.keep_fnames) {
            s.functions.each(function (d) {
                push_uniq(def.scope.enclosed, d);
            });
        }
        if (s === def.scope) break;
        s = s.parent_scope;
    }
});

AST_Symbol.DEFMETHOD("reference", function (options) {
    this.definition().references.push(this);
    this.mark_enclosed(options);
});

AST_Scope.DEFMETHOD("find_variable", function (name) {
    if (name instanceof AST_Symbol) name = name.name;
    return this.variables.get(name)
        || (this.parent_scope && this.parent_scope.find_variable(name));
});

AST_Scope.DEFMETHOD("def_function", function (symbol) {
    this.functions.set(symbol.name, this.def_variable(symbol));
});

AST_Scope.DEFMETHOD("def_variable", function (symbol) {
    var def;
    if (!this.variables.has(symbol.name)) {
        def = new SymbolDef(this, this.variables.size(), symbol);
        this.variables.set(symbol.name, def);
        def.global = !this.parent_scope;
    } else {
        def = this.variables.get(symbol.name);
        def.orig.push(symbol);
    }
    return symbol.thedef = def;
});

AST_Scope.DEFMETHOD("next_mangled", function (options) {
    var ext = this.enclosed;
    out: while (true) {
        var m = base54(++this.cname);
        if (!is_identifier(m)) continue; // skip over "do"

        // https://github.com/mishoo/UglifyJS2/issues/242 -- do not
        // shadow a name reserved from mangling.
        if (options.reserved.indexOf(m) >= 0) continue;

        // we must ensure that the mangled name does not shadow a name
        // from some parent scope that is referenced in this or in
        // inner scopes.
        for (var i = ext.length; --i >= 0;) {
            var sym = ext[i];
            var name = sym.mangled_name || (sym.unmangleable(options) && sym.name);
            if (m == name) {
                continue out;
            }
        }
        return m;
    }
});

AST_Function.DEFMETHOD("next_mangled", function (options, def) {
    // #179, #326
    // in Safari strict mode, something like (function x(x){...}) is a syntax error;
    // a function expression's argument cannot shadow the function expression's name

    var tricky_def = def.orig[0] instanceof AST_SymbolFunarg && this.name && this.name.definition();

    // the function's mangled_name is null when keep_fnames is true
    var tricky_name = tricky_def ? tricky_def.mangled_name || tricky_def.name : null;

    while (true) {
        var name = AST_Lambda.prototype.next_mangled.call(this, options, def);

        if (!tricky_name || tricky_name != name) {
            return name;
        }
    }
});

AST_Symbol.DEFMETHOD("unmangleable", function (options) {
    var def = this.definition();
    return !def || def.unmangleable(options);
});

// labels are always mangleable
AST_Label.DEFMETHOD("unmangleable", return_false);

AST_Symbol.DEFMETHOD("unreferenced", function () {
    return this.definition().references.length == 0
        && !(this.scope.uses_eval || this.scope.uses_with);
});

AST_Symbol.DEFMETHOD("definition", function () {
    return this.thedef;
});

AST_Symbol.DEFMETHOD("global", function () {
    return this.definition().global;
});

AST_Toplevel.DEFMETHOD("_default_mangler_options", function (options) {
    options = defaults(options, {
        eval: false,
        ie8: false,
        keep_fnames: false,
        reserved: [],
        toplevel: false,
    });
    if (!Array.isArray(options.reserved)) options.reserved = [];
    return options;
});

AST_Toplevel.DEFMETHOD("mangle_names", function (options) {
    options = this._default_mangler_options(options);

    // Never mangle arguments
    options.reserved.push('arguments');

    // We only need to mangle declaration nodes.  Special logic wired
    // into the code generator will display the mangled name if it's
    // present (and for AST_SymbolRef-s it'll use the mangled name of
    // the AST_SymbolDeclaration that it points to).
    var lname = -1;
    var to_mangle = [];

    if (options.cache) {
        this.globals.each(function (symbol) {
            if (options.reserved.indexOf(symbol.name) < 0) {
                to_mangle.push(symbol);
            }
        });
    }

    var tw = new TreeWalker(function (node, descend) {
        if (node instanceof AST_LabeledStatement) {
            // lname is incremented when we get to the AST_Label
            var save_nesting = lname;
            descend();
            lname = save_nesting;
            return true;        // don't descend again in TreeWalker
        }
        if (node instanceof AST_Scope) {
            var p = tw.parent(), a = [];
            node.variables.each(function (symbol) {
                if (options.reserved.indexOf(symbol.name) < 0) {
                    a.push(symbol);
                }
            });
            to_mangle.push.apply(to_mangle, a);
            return;
        }
        if (node instanceof AST_Label) {
            var name;
            do {
                name = base54(++lname);
            } while (!is_identifier(name));

            node.mangled_name = name;
            return true;
        }
        if (!options.ie8 && node instanceof AST_SymbolCatch) {
            to_mangle.push(node.definition());
            return;
        }
    });
    this.walk(tw);
    to_mangle.forEach(function (def) {
        def.mangle(options)
    });

    if (options.cache) {
        options.cache.cname = this.cname;
    }
});

AST_Toplevel.DEFMETHOD("compute_char_frequency", function (options) {
    options = this._default_mangler_options(options);
    try {
        AST_Node.prototype.print = function (stream, force_parens) {
            this._print(stream, force_parens);
            if (this instanceof AST_Symbol && !this.unmangleable(options)) {
                base54.consider(this.name, -1);
            } else if (options.properties) {
                if (this instanceof AST_Dot) {
                    base54.consider(this.property, -1);
                } else if (this instanceof AST_Sub) {
                    skip_string(this.property);
                }
            }
        };
        base54.consider(this.print_to_string(), 1);
    } finally {
        AST_Node.prototype.print = AST_Node.prototype._print;
    }
    base54.sort();

    function skip_string(node) {
        if (node instanceof AST_String) {
            base54.consider(node.value, -1);
        } else if (node instanceof AST_Conditional) {
            skip_string(node.consequent);
            skip_string(node.alternative);
        } else if (node instanceof AST_Sequence) {
            skip_string(node.expressions[node.expressions.length - 1]);
        }
    }
});

var base54 = (function () {
    var leading = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_".split("");
    var digits = "0123456789".split("");
    var chars, frequency;

    function reset() {
        frequency = Object.create(null);
        leading.forEach(function (ch) {
            frequency[ch] = 0;
        });
        digits.forEach(function (ch) {
            frequency[ch] = 0;
        });
    }

    base54.consider = function (str, delta) {
        for (var i = str.length; --i >= 0;) {
            frequency[str[i]] += delta;
        }
    };
    function compare(a, b) {
        return frequency[b] - frequency[a];
    }

    base54.sort = function () {
        chars = mergeSort(leading, compare).concat(mergeSort(digits, compare));
    };
    base54.reset = reset;
    reset();
    function base54(num) {
        var ret = "", base = 54;
        num++;
        do {
            num--;
            ret += chars[num % base];
            num = Math.floor(num / base);
            base = 64;
        } while (num > 0);
        return ret;
    };
    return base54;
})();


/*********** sourcemap.js ****************/

// a small wrapper around fitzgen's source-map library
function SourceMap(options) {
    options = defaults(options, {
        file: null,
        root: null,
        orig: null,

        orig_line_diff: 0,
        dest_line_diff: 0,
    });
    var generator = new MOZ_SourceMap.SourceMapGenerator({
        file: options.file,
        sourceRoot: options.root
    });
    var orig_map = options.orig && new MOZ_SourceMap.SourceMapConsumer(options.orig);

    if (orig_map && Array.isArray(options.orig.sources)) {
        orig_map._sources.toArray().forEach(function (source) {
            var sourceContent = orig_map.sourceContentFor(source, true);
            if (sourceContent) {
                generator.setSourceContent(source, sourceContent);
            }
        });
    }

    function add(source, gen_line, gen_col, orig_line, orig_col, name) {
        if (orig_map) {
            var info = orig_map.originalPositionFor({
                line: orig_line,
                column: orig_col
            });
            if (info.source === null) {
                return;
            }
            source = info.source;
            orig_line = info.line;
            orig_col = info.column;
            name = info.name || name;
        }
        generator.addMapping({
            generated: {line: gen_line + options.dest_line_diff, column: gen_col},
            original: {line: orig_line + options.orig_line_diff, column: orig_col},
            source: source,
            name: name
        });
    };
    return {
        add: add,
        get: function () {
            return generator
        },
        toString: function () {
            return JSON.stringify(generator.toJSON());
        }
    };
};





exports.Dictionary = Dictionary;
exports.TreeWalker = TreeWalker;
exports.TreeTransformer = TreeTransformer;
exports.minify = minify;
exports.minify = minify;
exports.minifyString = minifyString;
exports._push_uniq = push_uniq;

//节点类型会自动注册
//exports.AST_Node = AST_Node;
//exports.AST_Token = AST_Token;

/***************  node.js  ******************/
function describe_ast() {
    var out = OutputStream({beautify: true});

    function doitem(ctor) {
        out.print("AST_" + ctor.TYPE);
        var props = ctor.SELF_PROPS.filter(function (prop) {
            return !/^\$/.test(prop);
        });
        if (props.length > 0) {
            out.space();
            out.with_parens(function () {
                props.forEach(function (prop, i) {
                    if (i) out.space();
                    out.print(prop);
                });
            });
        }
        if (ctor.documentation) {
            out.space();
            out.print_string(ctor.documentation);
        }
        if (ctor.SUBCLASSES.length > 0) {
            out.space();
            out.with_block(function () {
                ctor.SUBCLASSES.forEach(function (ctor, i) {
                    out.indent();
                    doitem(ctor);
                    out.newline();
                });
            });
        }
    };
    doitem(AST_Node);
    return out + "\n";
}

function infer_options(options) {
    var result = minify("", options);
    return result.error && result.error.defs;
}

exports.default_options = function () {
    var defs = {};
    Object.keys(infer_options({0: 0})).forEach(function (component) {
        var options = {};
        options[component] = {0: 0};
        if (options = infer_options(options)) {
            defs[component] = options;
        }
    });
    return defs;
};